<?xml version="1.0" encoding="us-ascii"?>
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:t1="http://xbrl.org/2005/xbrldt">
  <link:roleRef roleURI="http://questar.com/role/DocumentAndEntityInformation" xlink:type="simple" xlink:href="str-20110930.xsd#DocumentAndEntityInformation" />
  <link:roleRef roleURI="http://questar.com/role/RecentAccountingDevelopment" xlink:type="simple" xlink:href="str-20110930.xsd#RecentAccountingDevelopment" />
  <link:roleRef roleURI="http://questar.com/role/DiscontinuedOperationsTables" xlink:type="simple" xlink:href="str-20110930.xsd#DiscontinuedOperationsTables" />
  <link:roleRef roleURI="http://questar.com/role/DiscontinuedOperationsDetails" xlink:type="simple" xlink:href="str-20110930.xsd#DiscontinuedOperationsDetails" />
  <link:roleRef roleURI="http://questar.com/role/DiscontinuedOperations" xlink:type="simple" xlink:href="str-20110930.xsd#DiscontinuedOperations" />
  <link:roleRef roleURI="http://questar.com/role/EmployeeBenefitsTables" xlink:type="simple" xlink:href="str-20110930.xsd#EmployeeBenefitsTables" />
  <link:roleRef roleURI="http://questar.com/role/EmployeeBenefitsDetails" xlink:type="simple" xlink:href="str-20110930.xsd#EmployeeBenefitsDetails" />
  <link:roleRef roleURI="http://questar.com/role/EmployeeBenefits" xlink:type="simple" xlink:href="str-20110930.xsd#EmployeeBenefits" />
  <link:roleRef roleURI="http://questar.com/role/OperationsByLineOfBusinessTables" xlink:type="simple" xlink:href="str-20110930.xsd#OperationsByLineOfBusinessTables" />
  <link:roleRef roleURI="http://questar.com/role/OperationsByLineOfBusinessDetails" xlink:type="simple" xlink:href="str-20110930.xsd#OperationsByLineOfBusinessDetails" />
  <link:roleRef roleURI="http://questar.com/role/OperationsByLineOfBusiness" xlink:type="simple" xlink:href="str-20110930.xsd#OperationsByLineOfBusiness" />
  <link:roleRef roleURI="http://questar.com/role/ShareBasedCompensationTables" xlink:type="simple" xlink:href="str-20110930.xsd#ShareBasedCompensationTables" />
  <link:roleRef roleURI="http://questar.com/role/ShareBasedCompensationDetails" xlink:type="simple" xlink:href="str-20110930.xsd#ShareBasedCompensationDetails" />
  <link:roleRef roleURI="http://questar.com/role/ShareBasedCompensation" xlink:type="simple" xlink:href="str-20110930.xsd#ShareBasedCompensation" />
  <link:roleRef roleURI="http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesTables" xlink:type="simple" xlink:href="str-20110930.xsd#DerivativeInstrumentsAndHedgingActivitiesTables" />
  <link:roleRef roleURI="http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesAdditionalInformationDetails" xlink:type="simple" xlink:href="str-20110930.xsd#DerivativeInstrumentsAndHedgingActivitiesAdditionalInformationDetails" />
  <link:roleRef roleURI="http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesAssetAndLiabilityDerivativeInstrumentsDesignatedAsHedgesInBalanceSheetsDetails" xlink:type="simple" xlink:href="str-20110930.xsd#DerivativeInstrumentsAndHedgingActivitiesAssetAndLiabilityDerivativeInstrumentsDesignatedAsHedgesInBalanceSheetsDetails" />
  <link:roleRef roleURI="http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesEffectsOnStatementsOfIncomeAndAociDetails" xlink:type="simple" xlink:href="str-20110930.xsd#DerivativeInstrumentsAndHedgingActivitiesEffectsOnStatementsOfIncomeAndAociDetails" />
  <link:roleRef roleURI="http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesDetails" xlink:type="simple" xlink:href="str-20110930.xsd#DerivativeInstrumentsAndHedgingActivitiesDetails" />
  <link:roleRef roleURI="http://questar.com/role/DerivativeInstrumentsAndHedgingActivities" xlink:type="simple" xlink:href="str-20110930.xsd#DerivativeInstrumentsAndHedgingActivities" />
  <link:roleRef roleURI="http://questar.com/role/FairValueMeasurementsTables" xlink:type="simple" xlink:href="str-20110930.xsd#FairValueMeasurementsTables" />
  <link:roleRef roleURI="http://questar.com/role/FairValueMeasurementsDetails" xlink:type="simple" xlink:href="str-20110930.xsd#FairValueMeasurementsDetails" />
  <link:roleRef roleURI="http://questar.com/role/FairValueMeasurements" xlink:type="simple" xlink:href="str-20110930.xsd#FairValueMeasurements" />
  <link:roleRef roleURI="http://questar.com/role/AssetRetirementObligationsTables" xlink:type="simple" xlink:href="str-20110930.xsd#AssetRetirementObligationsTables" />
  <link:roleRef roleURI="http://questar.com/role/AssetRetirementObligationsDetails" xlink:type="simple" xlink:href="str-20110930.xsd#AssetRetirementObligationsDetails" />
  <link:roleRef roleURI="http://questar.com/role/AssetRetirementObligations" xlink:type="simple" xlink:href="str-20110930.xsd#AssetRetirementObligations" />
  <link:roleRef roleURI="http://questar.com/role/EarningsPerShareTables" xlink:type="simple" xlink:href="str-20110930.xsd#EarningsPerShareTables" />
  <link:roleRef roleURI="http://questar.com/role/EarningsPerShareDetails" xlink:type="simple" xlink:href="str-20110930.xsd#EarningsPerShareDetails" />
  <link:roleRef roleURI="http://questar.com/role/EarningsPerShare" xlink:type="simple" xlink:href="str-20110930.xsd#EarningsPerShare" />
  <link:roleRef roleURI="http://questar.com/role/ComprehensiveIncomeTables" xlink:type="simple" xlink:href="str-20110930.xsd#ComprehensiveIncomeTables" />
  <link:roleRef roleURI="http://questar.com/role/ComprehensiveIncomeDetails" xlink:type="simple" xlink:href="str-20110930.xsd#ComprehensiveIncomeDetails" />
  <link:roleRef roleURI="http://questar.com/role/ComprehensiveIncome" xlink:type="simple" xlink:href="str-20110930.xsd#ComprehensiveIncome" />
  <link:roleRef roleURI="http://questar.com/role/BasisOfPresentationOfInterimFinancialStatementsPolicies" xlink:type="simple" xlink:href="str-20110930.xsd#BasisOfPresentationOfInterimFinancialStatementsPolicies" />
  <link:roleRef roleURI="http://questar.com/role/BasisOfPresentationOfInterimFinancialStatementsDetails" xlink:type="simple" xlink:href="str-20110930.xsd#BasisOfPresentationOfInterimFinancialStatementsDetails" />
  <link:roleRef roleURI="http://questar.com/role/BasisOfPresentationOfInterimFinancialStatements" xlink:type="simple" xlink:href="str-20110930.xsd#BasisOfPresentationOfInterimFinancialStatements" />
  <link:roleRef roleURI="http://questar.com/role/NatureOfBusinessDetails" xlink:type="simple" xlink:href="str-20110930.xsd#NatureOfBusinessDetails" />
  <link:roleRef roleURI="http://questar.com/role/NatureOfBusiness" xlink:type="simple" xlink:href="str-20110930.xsd#NatureOfBusiness" />
  <link:roleRef roleURI="http://questar.com/role/CondensedConsolidatedStatementsOfCashFlowsUnaudited" xlink:type="simple" xlink:href="str-20110930.xsd#CondensedConsolidatedStatementsOfCashFlowsUnaudited" />
  <link:roleRef roleURI="http://questar.com/role/CondensedConsolidatedBalanceSheetsUnaudited" xlink:type="simple" xlink:href="str-20110930.xsd#CondensedConsolidatedBalanceSheetsUnaudited" />
  <link:roleRef roleURI="http://questar.com/role/ConsolidatedStatementsOfIncomeUnaudited" xlink:type="simple" xlink:href="str-20110930.xsd#ConsolidatedStatementsOfIncomeUnaudited" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/ConsolidatedStatementsOfIncomeUnaudited">
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityInformationLineItems" xlink:label="EntityInformationLineItems" xlink:title="EntityInformationLineItems" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_GasDomesticRegulatedRevenueDistribution" xlink:label="GasDomesticRegulatedRevenueDistribution" xlink:title="GasDomesticRegulatedRevenueDistribution" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="GasDomesticRegulatedRevenueDistribution" xlink:title="definition: EntityInformationLineItems to GasDomesticRegulatedRevenueDistribution" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_GasDomesticRegulatedRevenueTransmission" xlink:label="GasDomesticRegulatedRevenueTransmission" xlink:title="GasDomesticRegulatedRevenueTransmission" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="GasDomesticRegulatedRevenueTransmission" xlink:title="definition: EntityInformationLineItems to GasDomesticRegulatedRevenueTransmission" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_NaturalGasProductionRevenue" xlink:label="NaturalGasProductionRevenue" xlink:title="NaturalGasProductionRevenue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="NaturalGasProductionRevenue" xlink:title="definition: EntityInformationLineItems to NaturalGasProductionRevenue" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_GasDomesticRegulatedRevenueTransmissionAffiliatedCompanies" xlink:label="GasDomesticRegulatedRevenueTransmissionAffiliatedCompanies" xlink:title="GasDomesticRegulatedRevenueTransmissionAffiliatedCompanies" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="GasDomesticRegulatedRevenueTransmissionAffiliatedCompanies" xlink:title="definition: EntityInformationLineItems to GasDomesticRegulatedRevenueTransmissionAffiliatedCompanies" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_GasDomesticRegulatedRevenueDistributionAffiliatedCompany" xlink:label="GasDomesticRegulatedRevenueDistributionAffiliatedCompany" xlink:title="GasDomesticRegulatedRevenueDistributionAffiliatedCompany" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="GasDomesticRegulatedRevenueDistributionAffiliatedCompany" xlink:title="definition: EntityInformationLineItems to GasDomesticRegulatedRevenueDistributionAffiliatedCompany" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_Revenues" xlink:label="Revenues" xlink:title="Revenues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="Revenues" xlink:title="definition: EntityInformationLineItems to Revenues" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CostOfGoodsSoldOilAndGas" xlink:label="CostOfGoodsSoldOilAndGas" xlink:title="CostOfGoodsSoldOilAndGas" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="CostOfGoodsSoldOilAndGas" xlink:title="definition: EntityInformationLineItems to CostOfGoodsSoldOilAndGas" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CostOfPurchasedOilAndGas" xlink:label="CostOfPurchasedOilAndGas" xlink:title="CostOfPurchasedOilAndGas" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="CostOfPurchasedOilAndGas" xlink:title="definition: EntityInformationLineItems to CostOfPurchasedOilAndGas" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CostOfPropertyRepairsAndMaintenance" xlink:label="CostOfPropertyRepairsAndMaintenance" xlink:title="CostOfPropertyRepairsAndMaintenance" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="CostOfPropertyRepairsAndMaintenance" xlink:title="definition: EntityInformationLineItems to CostOfPropertyRepairsAndMaintenance" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="GeneralAndAdministrativeExpense" xlink:title="GeneralAndAdministrativeExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="GeneralAndAdministrativeExpense" xlink:title="definition: EntityInformationLineItems to GeneralAndAdministrativeExpense" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_SeveranceCosts" xlink:label="SeveranceCosts" xlink:title="SeveranceCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="SeveranceCosts" xlink:title="definition: EntityInformationLineItems to SeveranceCosts" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_TaxesExcludingIncomeAndExciseTaxes" xlink:label="TaxesExcludingIncomeAndExciseTaxes" xlink:title="TaxesExcludingIncomeAndExciseTaxes" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="TaxesExcludingIncomeAndExciseTaxes" xlink:title="definition: EntityInformationLineItems to TaxesExcludingIncomeAndExciseTaxes" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DepreciationAndAmortization" xlink:label="DepreciationAndAmortization" xlink:title="DepreciationAndAmortization" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="DepreciationAndAmortization" xlink:title="definition: EntityInformationLineItems to DepreciationAndAmortization" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization" xlink:label="UtilitiesOperatingExpenseDepreciationAndAmortization" xlink:title="UtilitiesOperatingExpenseDepreciationAndAmortization" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="UtilitiesOperatingExpenseDepreciationAndAmortization" xlink:title="definition: EntityInformationLineItems to UtilitiesOperatingExpenseDepreciationAndAmortization" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_TaxesOther" xlink:label="TaxesOther" xlink:title="TaxesOther" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="TaxesOther" xlink:title="definition: EntityInformationLineItems to TaxesOther" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold" xlink:label="CostOfGoodsAndServicesSold" xlink:title="CostOfGoodsAndServicesSold" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="CostOfGoodsAndServicesSold" xlink:title="definition: EntityInformationLineItems to CostOfGoodsAndServicesSold" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="OperatingExpenses" xlink:title="OperatingExpenses" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="OperatingExpenses" xlink:title="definition: EntityInformationLineItems to OperatingExpenses" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_GainLossOnDispositionOfAssets" xlink:label="GainLossOnDispositionOfAssets" xlink:title="GainLossOnDispositionOfAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="GainLossOnDispositionOfAssets" xlink:title="definition: EntityInformationLineItems to GainLossOnDispositionOfAssets" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="OperatingIncomeLoss" xlink:title="OperatingIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="OperatingIncomeLoss" xlink:title="definition: EntityInformationLineItems to OperatingIncomeLoss" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_InvestmentIncomeNonoperating" xlink:label="InvestmentIncomeNonoperating" xlink:title="InvestmentIncomeNonoperating" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="InvestmentIncomeNonoperating" xlink:title="definition: EntityInformationLineItems to InvestmentIncomeNonoperating" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="IncomeLossFromEquityMethodInvestments" xlink:title="IncomeLossFromEquityMethodInvestments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeLossFromEquityMethodInvestments" xlink:title="definition: EntityInformationLineItems to IncomeLossFromEquityMethodInvestments" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_InterestExpense" xlink:label="InterestExpense" xlink:title="InterestExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="InterestExpense" xlink:title="definition: EntityInformationLineItems to InterestExpense" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:title="IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:title="definition: EntityInformationLineItems to IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="IncomeTaxExpenseBenefit" xlink:title="IncomeTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeTaxExpenseBenefit" xlink:title="definition: EntityInformationLineItems to IncomeTaxExpenseBenefit" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromContinuingOperations" xlink:label="IncomeLossFromContinuingOperations" xlink:title="IncomeLossFromContinuingOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeLossFromContinuingOperations" xlink:title="definition: EntityInformationLineItems to IncomeLossFromContinuingOperations" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:title="definition: EntityInformationLineItems to IncomeLossFromDiscontinuedOperationsNetOfTax" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" xlink:title="definition: EntityInformationLineItems to IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" xlink:title="definition: EntityInformationLineItems to IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="NetIncomeLoss" xlink:title="NetIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="NetIncomeLoss" xlink:title="definition: EntityInformationLineItems to NetIncomeLoss" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:label="IncomeLossFromContinuingOperationsPerBasicShare" xlink:title="IncomeLossFromContinuingOperationsPerBasicShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeLossFromContinuingOperationsPerBasicShare" xlink:title="definition: EntityInformationLineItems to IncomeLossFromContinuingOperationsPerBasicShare" order="31.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:title="definition: EntityInformationLineItems to IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" order="32.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="EarningsPerShareBasic" xlink:title="EarningsPerShareBasic" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="EarningsPerShareBasic" xlink:title="definition: EntityInformationLineItems to EarningsPerShareBasic" order="33.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare" xlink:label="IncomeLossFromContinuingOperationsPerDilutedShare" xlink:title="IncomeLossFromContinuingOperationsPerDilutedShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeLossFromContinuingOperationsPerDilutedShare" xlink:title="definition: EntityInformationLineItems to IncomeLossFromContinuingOperationsPerDilutedShare" order="34.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" xlink:title="definition: EntityInformationLineItems to IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" order="35.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="EarningsPerShareDiluted" xlink:title="EarningsPerShareDiluted" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="EarningsPerShareDiluted" xlink:title="definition: EntityInformationLineItems to EarningsPerShareDiluted" order="36.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntitiesTable" xlink:label="EntitiesTable" xlink:title="EntitiesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="EntityInformationLineItems" xlink:to="EntitiesTable" xlink:title="definition: EntityInformationLineItems to EntitiesTable" order="1.0" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QuestarPipelineMember" xlink:label="QuestarPipelineMember" xlink:title="QuestarPipelineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="QuestarPipelineMember" xlink:title="definition: EntityDomain to QuestarPipelineMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QuestarGasMember" xlink:label="QuestarGasMember" xlink:title="QuestarGasMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="QuestarGasMember" xlink:title="definition: EntityDomain to QuestarGasMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain_2" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LegalEntityAxis" xlink:to="EntityDomain_2" xlink:title="definition: LegalEntityAxis to EntityDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="EntitiesTable" xlink:to="LegalEntityAxis" xlink:title="definition: EntitiesTable to LegalEntityAxis" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/CondensedConsolidatedBalanceSheetsUnaudited">
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityInformationLineItems" xlink:label="EntityInformationLineItems" xlink:title="EntityInformationLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="CashAndCashEquivalentsAtCarryingValue" xlink:title="CashAndCashEquivalentsAtCarryingValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="CashAndCashEquivalentsAtCarryingValue" xlink:title="definition: EntityInformationLineItems to CashAndCashEquivalentsAtCarryingValue" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_NotesReceivableFromParent" xlink:label="NotesReceivableFromParent" xlink:title="NotesReceivableFromParent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="NotesReceivableFromParent" xlink:title="definition: EntityInformationLineItems to NotesReceivableFromParent" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeTaxReceivable" xlink:label="IncomeTaxReceivable" xlink:title="IncomeTaxReceivable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeTaxReceivable" xlink:title="definition: EntityInformationLineItems to IncomeTaxReceivable" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="AccountsReceivableNetCurrent" xlink:title="AccountsReceivableNetCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="AccountsReceivableNetCurrent" xlink:title="definition: EntityInformationLineItems to AccountsReceivableNetCurrent" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_UnbilledContractsReceivable" xlink:label="UnbilledContractsReceivable" xlink:title="UnbilledContractsReceivable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="UnbilledContractsReceivable" xlink:title="definition: EntityInformationLineItems to UnbilledContractsReceivable" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_AccountsReceivableFromAffiliates" xlink:label="AccountsReceivableFromAffiliates" xlink:title="AccountsReceivableFromAffiliates" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="AccountsReceivableFromAffiliates" xlink:title="definition: EntityInformationLineItems to AccountsReceivableFromAffiliates" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_EnergyRelatedInventoryGasStoredUnderground" xlink:label="EnergyRelatedInventoryGasStoredUnderground" xlink:title="EnergyRelatedInventoryGasStoredUnderground" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="EnergyRelatedInventoryGasStoredUnderground" xlink:title="definition: EntityInformationLineItems to EnergyRelatedInventoryGasStoredUnderground" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_OtherInventorySupplies" xlink:label="OtherInventorySupplies" xlink:title="OtherInventorySupplies" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="OtherInventorySupplies" xlink:title="definition: EntityInformationLineItems to OtherInventorySupplies" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_RegulatoryAssetsCurrent" xlink:label="RegulatoryAssetsCurrent" xlink:title="RegulatoryAssetsCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="RegulatoryAssetsCurrent" xlink:title="definition: EntityInformationLineItems to RegulatoryAssetsCurrent" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_PrepaidExpenseCurrent" xlink:label="PrepaidExpenseCurrent" xlink:title="PrepaidExpenseCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="PrepaidExpenseCurrent" xlink:title="definition: EntityInformationLineItems to PrepaidExpenseCurrent" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DeferredTaxAssetsNetCurrent" xlink:label="DeferredTaxAssetsNetCurrent" xlink:title="DeferredTaxAssetsNetCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="DeferredTaxAssetsNetCurrent" xlink:title="definition: EntityInformationLineItems to DeferredTaxAssetsNetCurrent" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="AssetsCurrent" xlink:title="AssetsCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="AssetsCurrent" xlink:title="definition: EntityInformationLineItems to AssetsCurrent" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="PropertyPlantAndEquipmentGross" xlink:title="PropertyPlantAndEquipmentGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="PropertyPlantAndEquipmentGross" xlink:title="definition: EntityInformationLineItems to PropertyPlantAndEquipmentGross" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:title="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:title="definition: EntityInformationLineItems to AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNet" xlink:label="DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNet" xlink:title="DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNet" xlink:title="definition: EntityInformationLineItems to DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNet" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:label="InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:title="InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:title="definition: EntityInformationLineItems to InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_RegulatoryAssetsNoncurrent" xlink:label="RegulatoryAssetsNoncurrent" xlink:title="RegulatoryAssetsNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="RegulatoryAssetsNoncurrent" xlink:title="definition: EntityInformationLineItems to RegulatoryAssetsNoncurrent" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_Goodwill" xlink:label="Goodwill" xlink:title="Goodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="Goodwill" xlink:title="definition: EntityInformationLineItems to Goodwill" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="OtherAssetsNoncurrent" xlink:title="OtherAssetsNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="OtherAssetsNoncurrent" xlink:title="definition: EntityInformationLineItems to OtherAssetsNoncurrent" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_RegulatoryAndOtherNoncurrentAssets" xlink:label="RegulatoryAndOtherNoncurrentAssets" xlink:title="RegulatoryAndOtherNoncurrentAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="RegulatoryAndOtherNoncurrentAssets" xlink:title="definition: EntityInformationLineItems to RegulatoryAndOtherNoncurrentAssets" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_Assets" xlink:label="Assets" xlink:title="Assets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="Assets" xlink:title="definition: EntityInformationLineItems to Assets" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_BankOverdrafts" xlink:label="BankOverdrafts" xlink:title="BankOverdrafts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="BankOverdrafts" xlink:title="definition: EntityInformationLineItems to BankOverdrafts" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_NotesPayableToParent" xlink:label="NotesPayableToParent" xlink:title="NotesPayableToParent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="NotesPayableToParent" xlink:title="definition: EntityInformationLineItems to NotesPayableToParent" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShortTermBorrowings" xlink:label="ShortTermBorrowings" xlink:title="ShortTermBorrowings" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="ShortTermBorrowings" xlink:title="definition: EntityInformationLineItems to ShortTermBorrowings" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="AccountsPayableCurrent" xlink:title="AccountsPayableCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="AccountsPayableCurrent" xlink:title="definition: EntityInformationLineItems to AccountsPayableCurrent" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_AccountsPayableRelatedPartiesCurrent" xlink:label="AccountsPayableRelatedPartiesCurrent" xlink:title="AccountsPayableRelatedPartiesCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="AccountsPayableRelatedPartiesCurrent" xlink:title="definition: EntityInformationLineItems to AccountsPayableRelatedPartiesCurrent" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CustomerAdvancesCurrent" xlink:label="CustomerAdvancesCurrent" xlink:title="CustomerAdvancesCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="CustomerAdvancesCurrent" xlink:title="definition: EntityInformationLineItems to CustomerAdvancesCurrent" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_RegulatoryLiabilityCurrent" xlink:label="RegulatoryLiabilityCurrent" xlink:title="RegulatoryLiabilityCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="RegulatoryLiabilityCurrent" xlink:title="definition: EntityInformationLineItems to RegulatoryLiabilityCurrent" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_LongTermDebtCurrent" xlink:label="LongTermDebtCurrent" xlink:title="LongTermDebtCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="LongTermDebtCurrent" xlink:title="definition: EntityInformationLineItems to LongTermDebtCurrent" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="LiabilitiesCurrent" xlink:title="LiabilitiesCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="LiabilitiesCurrent" xlink:title="definition: EntityInformationLineItems to LiabilitiesCurrent" order="31.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="LongTermDebtNoncurrent" xlink:title="LongTermDebtNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="LongTermDebtNoncurrent" xlink:title="definition: EntityInformationLineItems to LongTermDebtNoncurrent" order="32.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DeferredTaxLiabilitiesNoncurrent" xlink:label="DeferredTaxLiabilitiesNoncurrent" xlink:title="DeferredTaxLiabilitiesNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="DeferredTaxLiabilitiesNoncurrent" xlink:title="definition: EntityInformationLineItems to DeferredTaxLiabilitiesNoncurrent" order="33.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_AssetRetirementObligationsNoncurrent" xlink:label="AssetRetirementObligationsNoncurrent" xlink:title="AssetRetirementObligationsNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="AssetRetirementObligationsNoncurrent" xlink:title="definition: EntityInformationLineItems to AssetRetirementObligationsNoncurrent" order="34.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent" xlink:label="PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent" xlink:title="PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent" xlink:title="definition: EntityInformationLineItems to PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent" order="35.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_CustomerContributionsInAidOfConstruction" xlink:label="CustomerContributionsInAidOfConstruction" xlink:title="CustomerContributionsInAidOfConstruction" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="CustomerContributionsInAidOfConstruction" xlink:title="definition: EntityInformationLineItems to CustomerContributionsInAidOfConstruction" order="36.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_RegulatoryAndOtherNoncurrentLiabilities" xlink:label="RegulatoryAndOtherNoncurrentLiabilities" xlink:title="RegulatoryAndOtherNoncurrentLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="RegulatoryAndOtherNoncurrentLiabilities" xlink:title="definition: EntityInformationLineItems to RegulatoryAndOtherNoncurrentLiabilities" order="37.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CommonStockValue" xlink:label="CommonStockValue" xlink:title="CommonStockValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="CommonStockValue" xlink:title="definition: EntityInformationLineItems to CommonStockValue" order="38.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="AdditionalPaidInCapital" xlink:title="AdditionalPaidInCapital" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="AdditionalPaidInCapital" xlink:title="definition: EntityInformationLineItems to AdditionalPaidInCapital" order="39.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="RetainedEarningsAccumulatedDeficit" xlink:title="RetainedEarningsAccumulatedDeficit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="RetainedEarningsAccumulatedDeficit" xlink:title="definition: EntityInformationLineItems to RetainedEarningsAccumulatedDeficit" order="40.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:title="AccumulatedOtherComprehensiveIncomeLossNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:title="definition: EntityInformationLineItems to AccumulatedOtherComprehensiveIncomeLossNetOfTax" order="41.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="StockholdersEquity" xlink:title="StockholdersEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="StockholdersEquity" xlink:title="definition: EntityInformationLineItems to StockholdersEquity" order="42.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="LiabilitiesAndStockholdersEquity" xlink:title="LiabilitiesAndStockholdersEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="LiabilitiesAndStockholdersEquity" xlink:title="definition: EntityInformationLineItems to LiabilitiesAndStockholdersEquity" order="43.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntitiesTable" xlink:label="EntitiesTable" xlink:title="EntitiesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="EntityInformationLineItems" xlink:to="EntitiesTable" xlink:title="definition: EntityInformationLineItems to EntitiesTable" order="1.0" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QuestarPipelineMember" xlink:label="QuestarPipelineMember" xlink:title="QuestarPipelineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="QuestarPipelineMember" xlink:title="definition: EntityDomain to QuestarPipelineMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QuestarGasMember" xlink:label="QuestarGasMember" xlink:title="QuestarGasMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="QuestarGasMember" xlink:title="definition: EntityDomain to QuestarGasMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain_2" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LegalEntityAxis" xlink:to="EntityDomain_2" xlink:title="definition: LegalEntityAxis to EntityDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="EntitiesTable" xlink:to="LegalEntityAxis" xlink:title="definition: EntitiesTable to LegalEntityAxis" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/CondensedConsolidatedStatementsOfCashFlowsUnaudited">
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityInformationLineItems" xlink:label="EntityInformationLineItems" xlink:title="EntityInformationLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ProfitLoss" xlink:label="ProfitLoss" xlink:title="ProfitLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="ProfitLoss" xlink:title="definition: EntityInformationLineItems to ProfitLoss" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:title="definition: EntityInformationLineItems to IncomeLossFromDiscontinuedOperationsNetOfTax" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="DepreciationDepletionAndAmortization" xlink:title="DepreciationDepletionAndAmortization" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="DepreciationDepletionAndAmortization" xlink:title="definition: EntityInformationLineItems to DepreciationDepletionAndAmortization" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_DepreciationAndAmortizationExpense" xlink:label="DepreciationAndAmortizationExpense" xlink:title="DepreciationAndAmortizationExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="DepreciationAndAmortizationExpense" xlink:title="definition: EntityInformationLineItems to DepreciationAndAmortizationExpense" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:label="DeferredIncomeTaxExpenseBenefit" xlink:title="DeferredIncomeTaxExpenseBenefit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="DeferredIncomeTaxExpenseBenefit" xlink:title="definition: EntityInformationLineItems to DeferredIncomeTaxExpenseBenefit" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="ShareBasedCompensation" xlink:title="ShareBasedCompensation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="ShareBasedCompensation" xlink:title="definition: EntityInformationLineItems to ShareBasedCompensation" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:label="GainLossOnSaleOfPropertyPlantEquipment" xlink:title="GainLossOnSaleOfPropertyPlantEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="GainLossOnSaleOfPropertyPlantEquipment" xlink:title="definition: EntityInformationLineItems to GainLossOnSaleOfPropertyPlantEquipment" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="IncomeLossFromEquityMethodInvestments" xlink:title="IncomeLossFromEquityMethodInvestments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeLossFromEquityMethodInvestments" xlink:title="definition: EntityInformationLineItems to IncomeLossFromEquityMethodInvestments" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_EquityMethodInvestmentDividendsOrDistributions" xlink:label="EquityMethodInvestmentDividendsOrDistributions" xlink:title="EquityMethodInvestmentDividendsOrDistributions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="EquityMethodInvestmentDividendsOrDistributions" xlink:title="definition: EntityInformationLineItems to EquityMethodInvestmentDividendsOrDistributions" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapital" xlink:label="IncreaseDecreaseInOperatingCapital" xlink:title="IncreaseDecreaseInOperatingCapital" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncreaseDecreaseInOperatingCapital" xlink:title="definition: EntityInformationLineItems to IncreaseDecreaseInOperatingCapital" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:label="NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:title="NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:title="definition: EntityInformationLineItems to NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="PaymentsToAcquirePropertyPlantAndEquipment" xlink:title="PaymentsToAcquirePropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="PaymentsToAcquirePropertyPlantAndEquipment" xlink:title="definition: EntityInformationLineItems to PaymentsToAcquirePropertyPlantAndEquipment" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_AdvancesToUnconsolidatedAffiliate" xlink:label="AdvancesToUnconsolidatedAffiliate" xlink:title="AdvancesToUnconsolidatedAffiliate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="AdvancesToUnconsolidatedAffiliate" xlink:title="definition: EntityInformationLineItems to AdvancesToUnconsolidatedAffiliate" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_PaymentsForProceedsFromRemovalCosts" xlink:label="PaymentsForProceedsFromRemovalCosts" xlink:title="PaymentsForProceedsFromRemovalCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="PaymentsForProceedsFromRemovalCosts" xlink:title="definition: EntityInformationLineItems to PaymentsForProceedsFromRemovalCosts" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ProceedsFromSaleOfProductiveAssets" xlink:label="ProceedsFromSaleOfProductiveAssets" xlink:title="ProceedsFromSaleOfProductiveAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="ProceedsFromSaleOfProductiveAssets" xlink:title="definition: EntityInformationLineItems to ProceedsFromSaleOfProductiveAssets" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_PaymentsToAcquireNotesReceivable" xlink:label="PaymentsToAcquireNotesReceivable" xlink:title="PaymentsToAcquireNotesReceivable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="PaymentsToAcquireNotesReceivable" xlink:title="definition: EntityInformationLineItems to PaymentsToAcquireNotesReceivable" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ProceedsFromContributionsFromParent" xlink:label="ProceedsFromContributionsFromParent" xlink:title="ProceedsFromContributionsFromParent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="ProceedsFromContributionsFromParent" xlink:title="definition: EntityInformationLineItems to ProceedsFromContributionsFromParent" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:label="NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:title="NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:title="definition: EntityInformationLineItems to NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="ProceedsFromIssuanceOfCommonStock" xlink:title="ProceedsFromIssuanceOfCommonStock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="ProceedsFromIssuanceOfCommonStock" xlink:title="definition: EntityInformationLineItems to ProceedsFromIssuanceOfCommonStock" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="PaymentsForRepurchaseOfCommonStock" xlink:title="PaymentsForRepurchaseOfCommonStock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="PaymentsForRepurchaseOfCommonStock" xlink:title="definition: EntityInformationLineItems to PaymentsForRepurchaseOfCommonStock" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ProceedsFromRepaymentsOfShortTermDebt" xlink:label="ProceedsFromRepaymentsOfShortTermDebt" xlink:title="ProceedsFromRepaymentsOfShortTermDebt" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="ProceedsFromRepaymentsOfShortTermDebt" xlink:title="definition: EntityInformationLineItems to ProceedsFromRepaymentsOfShortTermDebt" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ProceedsFromRepaymentsOfNotesPayable" xlink:label="ProceedsFromRepaymentsOfNotesPayable" xlink:title="ProceedsFromRepaymentsOfNotesPayable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="ProceedsFromRepaymentsOfNotesPayable" xlink:title="definition: EntityInformationLineItems to ProceedsFromRepaymentsOfNotesPayable" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ChangeInNotesReceivableFromParent" xlink:label="ChangeInNotesReceivableFromParent" xlink:title="ChangeInNotesReceivableFromParent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="ChangeInNotesReceivableFromParent" xlink:title="definition: EntityInformationLineItems to ChangeInNotesReceivableFromParent" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ChangeInNotesPayableToParent" xlink:label="ChangeInNotesPayableToParent" xlink:title="ChangeInNotesPayableToParent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="ChangeInNotesPayableToParent" xlink:title="definition: EntityInformationLineItems to ChangeInNotesPayableToParent" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_RepaymentsOfLongTermDebt" xlink:label="RepaymentsOfLongTermDebt" xlink:title="RepaymentsOfLongTermDebt" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="RepaymentsOfLongTermDebt" xlink:title="definition: EntityInformationLineItems to RepaymentsOfLongTermDebt" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_PaymentsOfDebtIssuanceCosts" xlink:label="PaymentsOfDebtIssuanceCosts" xlink:title="PaymentsOfDebtIssuanceCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="PaymentsOfDebtIssuanceCosts" xlink:title="definition: EntityInformationLineItems to PaymentsOfDebtIssuanceCosts" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncreaseDecreaseInOutstandingChecksFinancingActivities" xlink:label="IncreaseDecreaseInOutstandingChecksFinancingActivities" xlink:title="IncreaseDecreaseInOutstandingChecksFinancingActivities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncreaseDecreaseInOutstandingChecksFinancingActivities" xlink:title="definition: EntityInformationLineItems to IncreaseDecreaseInOutstandingChecksFinancingActivities" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_PaymentsOfDividends" xlink:label="PaymentsOfDividends" xlink:title="PaymentsOfDividends" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="PaymentsOfDividends" xlink:title="definition: EntityInformationLineItems to PaymentsOfDividends" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:label="ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:title="ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:title="definition: EntityInformationLineItems to ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:label="NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:title="NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:title="definition: EntityInformationLineItems to NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" order="31.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_NetCashProvidedByUsedInContinuingOperations" xlink:label="NetCashProvidedByUsedInContinuingOperations" xlink:title="NetCashProvidedByUsedInContinuingOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="NetCashProvidedByUsedInContinuingOperations" xlink:title="definition: EntityInformationLineItems to NetCashProvidedByUsedInContinuingOperations" order="32.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations" xlink:label="CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations" xlink:title="CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations" xlink:title="definition: EntityInformationLineItems to CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations" order="33.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations" xlink:label="CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations" xlink:title="CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations" xlink:title="definition: EntityInformationLineItems to CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations" order="34.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations" xlink:label="CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations" xlink:title="CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations" xlink:title="definition: EntityInformationLineItems to CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations" order="35.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_NetCashProvidedByUsedInDiscontinuedOperations" xlink:label="NetCashProvidedByUsedInDiscontinuedOperations" xlink:title="NetCashProvidedByUsedInDiscontinuedOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="NetCashProvidedByUsedInDiscontinuedOperations" xlink:title="definition: EntityInformationLineItems to NetCashProvidedByUsedInDiscontinuedOperations" order="36.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:title="CashAndCashEquivalentsPeriodIncreaseDecrease" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:title="definition: EntityInformationLineItems to CashAndCashEquivalentsPeriodIncreaseDecrease" order="37.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="CashAndCashEquivalentsAtCarryingValue" xlink:title="CashAndCashEquivalentsAtCarryingValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="CashAndCashEquivalentsAtCarryingValue" xlink:title="definition: EntityInformationLineItems to CashAndCashEquivalentsAtCarryingValue" order="38.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntitiesTable" xlink:label="EntitiesTable" xlink:title="EntitiesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="EntityInformationLineItems" xlink:to="EntitiesTable" xlink:title="definition: EntityInformationLineItems to EntitiesTable" order="1.0" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QuestarPipelineMember" xlink:label="QuestarPipelineMember" xlink:title="QuestarPipelineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="QuestarPipelineMember" xlink:title="definition: EntityDomain to QuestarPipelineMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QuestarGasMember" xlink:label="QuestarGasMember" xlink:title="QuestarGasMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="QuestarGasMember" xlink:title="definition: EntityDomain to QuestarGasMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain_2" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LegalEntityAxis" xlink:to="EntityDomain_2" xlink:title="definition: LegalEntityAxis to EntityDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="EntitiesTable" xlink:to="LegalEntityAxis" xlink:title="definition: EntitiesTable to LegalEntityAxis" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/NatureOfBusiness" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/NatureOfBusinessDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/BasisOfPresentationOfInterimFinancialStatements" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/BasisOfPresentationOfInterimFinancialStatementsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/BasisOfPresentationOfInterimFinancialStatementsPolicies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/ComprehensiveIncome" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/ComprehensiveIncomeDetails">
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityInformationLineItems" xlink:label="EntityInformationLineItems" xlink:title="EntityInformationLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ProfitLoss" xlink:label="ProfitLoss" xlink:title="ProfitLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="ProfitLoss" xlink:title="definition: EntityInformationLineItems to ProfitLoss" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_OtherComprehensiveIncomeEmployeeBenefitsAdjustmentBeforeTax" xlink:label="OtherComprehensiveIncomeEmployeeBenefitsAdjustmentBeforeTax" xlink:title="OtherComprehensiveIncomeEmployeeBenefitsAdjustmentBeforeTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="OtherComprehensiveIncomeEmployeeBenefitsAdjustmentBeforeTax" xlink:title="definition: EntityInformationLineItems to OtherComprehensiveIncomeEmployeeBenefitsAdjustmentBeforeTax" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_OtherComprehensiveIncomeAvailableForSaleSecuritiesAdjustmentBeforeTaxPeriodIncreaseDecrease" xlink:label="OtherComprehensiveIncomeAvailableForSaleSecuritiesAdjustmentBeforeTaxPeriodIncreaseDecrease" xlink:title="OtherComprehensiveIncomeAvailableForSaleSecuritiesAdjustmentBeforeTaxPeriodIncreaseDecrease" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="OtherComprehensiveIncomeAvailableForSaleSecuritiesAdjustmentBeforeTaxPeriodIncreaseDecrease" xlink:title="definition: EntityInformationLineItems to OtherComprehensiveIncomeAvailableForSaleSecuritiesAdjustmentBeforeTaxPeriodIncreaseDecrease" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_OtherComprehensiveIncomeUnrealizedGainLossOnInterestRateCashFlowHedges" xlink:label="OtherComprehensiveIncomeUnrealizedGainLossOnInterestRateCashFlowHedges" xlink:title="OtherComprehensiveIncomeUnrealizedGainLossOnInterestRateCashFlowHedges" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="OtherComprehensiveIncomeUnrealizedGainLossOnInterestRateCashFlowHedges" xlink:title="definition: EntityInformationLineItems to OtherComprehensiveIncomeUnrealizedGainLossOnInterestRateCashFlowHedges" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax" xlink:label="OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax" xlink:title="OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax" xlink:title="definition: EntityInformationLineItems to OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTax" xlink:label="OtherComprehensiveIncomeLossTax" xlink:title="OtherComprehensiveIncomeLossTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="OtherComprehensiveIncomeLossTax" xlink:title="definition: EntityInformationLineItems to OtherComprehensiveIncomeLossTax" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" xlink:label="OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" xlink:title="OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" xlink:title="definition: EntityInformationLineItems to OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:label="ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:title="ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:title="definition: EntityInformationLineItems to ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" xlink:title="definition: EntityInformationLineItems to IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="ComprehensiveIncomeNetOfTax" xlink:title="ComprehensiveIncomeNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="ComprehensiveIncomeNetOfTax" xlink:title="definition: EntityInformationLineItems to ComprehensiveIncomeNetOfTax" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax" xlink:label="AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax" xlink:title="AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax" xlink:title="definition: EntityInformationLineItems to AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" xlink:label="AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" xlink:title="AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" xlink:title="definition: EntityInformationLineItems to AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax" xlink:label="AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax" xlink:title="AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax" xlink:title="definition: EntityInformationLineItems to AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:title="AccumulatedOtherComprehensiveIncomeLossNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityInformationLineItems" xlink:to="AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:title="definition: EntityInformationLineItems to AccumulatedOtherComprehensiveIncomeLossNetOfTax" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntitiesTable" xlink:label="EntitiesTable" xlink:title="EntitiesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="EntityInformationLineItems" xlink:to="EntitiesTable" xlink:title="definition: EntityInformationLineItems to EntitiesTable" order="1.0" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QuestarPipelineMember" xlink:label="QuestarPipelineMember" xlink:title="QuestarPipelineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="QuestarPipelineMember" xlink:title="definition: EntityDomain to QuestarPipelineMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain_2" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LegalEntityAxis" xlink:to="EntityDomain_2" xlink:title="definition: LegalEntityAxis to EntityDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="EntitiesTable" xlink:to="LegalEntityAxis" xlink:title="definition: EntitiesTable to LegalEntityAxis" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/ComprehensiveIncomeTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/EarningsPerShare" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/EarningsPerShareDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/EarningsPerShareTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/AssetRetirementObligations" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/AssetRetirementObligationsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/AssetRetirementObligationsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/FairValueMeasurements" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/FairValueMeasurementsDetails">
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:title="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure" xlink:label="CashAndCashEquivalentsFairValueDisclosure" xlink:title="CashAndCashEquivalentsFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="CashAndCashEquivalentsFairValueDisclosure" xlink:title="definition: FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems to CashAndCashEquivalentsFairValueDisclosure" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_NotesReceivableRelatedParties" xlink:label="NotesReceivableRelatedParties" xlink:title="NotesReceivableRelatedParties" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="NotesReceivableRelatedParties" xlink:title="definition: FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems to NotesReceivableRelatedParties" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_InvestmentsFairValueDisclosure" xlink:label="InvestmentsFairValueDisclosure" xlink:title="InvestmentsFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="InvestmentsFairValueDisclosure" xlink:title="definition: FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems to InvestmentsFairValueDisclosure" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ChecksOutstandingInExcessOfCashBalancesFairValueDisclosure" xlink:label="ChecksOutstandingInExcessOfCashBalancesFairValueDisclosure" xlink:title="ChecksOutstandingInExcessOfCashBalancesFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="ChecksOutstandingInExcessOfCashBalancesFairValueDisclosure" xlink:title="definition: FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems to ChecksOutstandingInExcessOfCashBalancesFairValueDisclosure" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShortTermDebtFairValueDisclosure" xlink:label="ShortTermDebtFairValueDisclosure" xlink:title="ShortTermDebtFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="ShortTermDebtFairValueDisclosure" xlink:title="definition: FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems to ShortTermDebtFairValueDisclosure" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_NotesPayableRelatedPartiesCurrentAndNoncurrent" xlink:label="NotesPayableRelatedPartiesCurrentAndNoncurrent" xlink:title="NotesPayableRelatedPartiesCurrentAndNoncurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="NotesPayableRelatedPartiesCurrentAndNoncurrent" xlink:title="definition: FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems to NotesPayableRelatedPartiesCurrentAndNoncurrent" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_LongTermDebtIncludingCurrentPortionFairValueDisclosure" xlink:label="LongTermDebtIncludingCurrentPortionFairValueDisclosure" xlink:title="LongTermDebtIncludingCurrentPortionFairValueDisclosure" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="LongTermDebtIncludingCurrentPortionFairValueDisclosure" xlink:title="definition: FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems to LongTermDebtIncludingCurrentPortionFairValueDisclosure" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="FairValueByBalanceSheetGroupingTable" xlink:title="FairValueByBalanceSheetGroupingTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="FairValueByBalanceSheetGroupingTable" xlink:title="definition: FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems to FairValueByBalanceSheetGroupingTable" order="1.0" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="FairValueDisclosureItemAmountsDomain" xlink:title="FairValueDisclosureItemAmountsDomain" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:label="CarryingReportedAmountFairValueDisclosureMember" xlink:title="CarryingReportedAmountFairValueDisclosureMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueDisclosureItemAmountsDomain" xlink:to="CarryingReportedAmountFairValueDisclosureMember" xlink:title="definition: FairValueDisclosureItemAmountsDomain to CarryingReportedAmountFairValueDisclosureMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="EstimateOfFairValueFairValueDisclosureMember" xlink:title="EstimateOfFairValueFairValueDisclosureMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueDisclosureItemAmountsDomain" xlink:to="EstimateOfFairValueFairValueDisclosureMember" xlink:title="definition: FairValueDisclosureItemAmountsDomain to EstimateOfFairValueFairValueDisclosureMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis" xlink:label="FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis" xlink:title="FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis" xlink:to="FairValueDisclosureItemAmountsDomain" xlink:title="definition: FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis to FairValueDisclosureItemAmountsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="FairValueDisclosureItemAmountsDomain_2" xlink:title="FairValueDisclosureItemAmountsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis" xlink:to="FairValueDisclosureItemAmountsDomain_2" xlink:title="definition: FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis to FairValueDisclosureItemAmountsDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueByBalanceSheetGroupingTable" xlink:to="FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis" xlink:title="definition: FairValueByBalanceSheetGroupingTable to FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QuestarGasMember" xlink:label="QuestarGasMember" xlink:title="QuestarGasMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="QuestarGasMember" xlink:title="definition: EntityDomain to QuestarGasMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QuestarPipelineMember" xlink:label="QuestarPipelineMember" xlink:title="QuestarPipelineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="QuestarPipelineMember" xlink:title="definition: EntityDomain to QuestarPipelineMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain_2" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LegalEntityAxis" xlink:to="EntityDomain_2" xlink:title="definition: LegalEntityAxis to EntityDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueByBalanceSheetGroupingTable" xlink:to="LegalEntityAxis" xlink:title="definition: FairValueByBalanceSheetGroupingTable to LegalEntityAxis" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/FairValueMeasurementsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/DerivativeInstrumentsAndHedgingActivities" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesEffectsOnStatementsOfIncomeAndAociDetails">
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:label="DerivativeInstrumentsGainLossLineItems" xlink:title="DerivativeInstrumentsGainLossLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossRecognizedInIncomeNet" xlink:label="DerivativeInstrumentsGainLossRecognizedInIncomeNet" xlink:title="DerivativeInstrumentsGainLossRecognizedInIncomeNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeInstrumentsGainLossLineItems" xlink:to="DerivativeInstrumentsGainLossRecognizedInIncomeNet" xlink:title="definition: DerivativeInstrumentsGainLossLineItems to DerivativeInstrumentsGainLossRecognizedInIncomeNet" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" xlink:label="DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" xlink:title="DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeInstrumentsGainLossLineItems" xlink:to="DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" xlink:title="definition: DerivativeInstrumentsGainLossLineItems to DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:label="DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:title="DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DerivativeInstrumentsGainLossLineItems" xlink:to="DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:title="definition: DerivativeInstrumentsGainLossLineItems to DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" order="1.0" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_HedgingRelationshipDomain" xlink:label="HedgingRelationshipDomain" xlink:title="HedgingRelationshipDomain" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_FairValueHedgingMember" xlink:label="FairValueHedgingMember" xlink:title="FairValueHedgingMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="HedgingRelationshipDomain" xlink:to="FairValueHedgingMember" xlink:title="definition: HedgingRelationshipDomain to FairValueHedgingMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:label="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:title="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:to="HedgingRelationshipDomain" xlink:title="definition: DerivativeInstrumentsGainLossByHedgingRelationshipAxis to HedgingRelationshipDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_HedgingRelationshipDomain" xlink:label="HedgingRelationshipDomain_2" xlink:title="HedgingRelationshipDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:to="HedgingRelationshipDomain_2" xlink:title="definition: DerivativeInstrumentsGainLossByHedgingRelationshipAxis to HedgingRelationshipDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:to="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:title="definition: DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable to DerivativeInstrumentsGainLossByHedgingRelationshipAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeStatementAndOtherComprehensiveIncomeLocationDomain" xlink:label="IncomeStatementAndOtherComprehensiveIncomeLocationDomain" xlink:title="IncomeStatementAndOtherComprehensiveIncomeLocationDomain" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_InterestExpenseMember" xlink:label="InterestExpenseMember" xlink:title="InterestExpenseMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementAndOtherComprehensiveIncomeLocationDomain" xlink:to="InterestExpenseMember" xlink:title="definition: IncomeStatementAndOtherComprehensiveIncomeLocationDomain to InterestExpenseMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByIncomeStatementLocationAxis" xlink:label="DerivativeInstrumentsGainLossByIncomeStatementLocationAxis" xlink:title="DerivativeInstrumentsGainLossByIncomeStatementLocationAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DerivativeInstrumentsGainLossByIncomeStatementLocationAxis" xlink:to="IncomeStatementAndOtherComprehensiveIncomeLocationDomain" xlink:title="definition: DerivativeInstrumentsGainLossByIncomeStatementLocationAxis to IncomeStatementAndOtherComprehensiveIncomeLocationDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeStatementAndOtherComprehensiveIncomeLocationDomain" xlink:label="IncomeStatementAndOtherComprehensiveIncomeLocationDomain_2" xlink:title="IncomeStatementAndOtherComprehensiveIncomeLocationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DerivativeInstrumentsGainLossByIncomeStatementLocationAxis" xlink:to="IncomeStatementAndOtherComprehensiveIncomeLocationDomain_2" xlink:title="definition: DerivativeInstrumentsGainLossByIncomeStatementLocationAxis to IncomeStatementAndOtherComprehensiveIncomeLocationDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:to="DerivativeInstrumentsGainLossByIncomeStatementLocationAxis" xlink:title="definition: DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable to DerivativeInstrumentsGainLossByIncomeStatementLocationAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="DerivativeContractTypeDomain" xlink:title="DerivativeContractTypeDomain" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_InterestRateDerivativeInstrumentMember" xlink:label="InterestRateDerivativeInstrumentMember" xlink:title="InterestRateDerivativeInstrumentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeContractTypeDomain" xlink:to="InterestRateDerivativeInstrumentMember" xlink:title="definition: DerivativeContractTypeDomain to InterestRateDerivativeInstrumentMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_NotesDue2016275Member" xlink:label="NotesDue2016275Member" xlink:title="NotesDue2016275Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeContractTypeDomain" xlink:to="NotesDue2016275Member" xlink:title="definition: DerivativeContractTypeDomain to NotesDue2016275Member" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByDerivativeInstrumentRiskAxis" xlink:label="DerivativeInstrumentsGainLossByDerivativeInstrumentRiskAxis" xlink:title="DerivativeInstrumentsGainLossByDerivativeInstrumentRiskAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DerivativeInstrumentsGainLossByDerivativeInstrumentRiskAxis" xlink:to="DerivativeContractTypeDomain" xlink:title="definition: DerivativeInstrumentsGainLossByDerivativeInstrumentRiskAxis to DerivativeContractTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="DerivativeContractTypeDomain_2" xlink:title="DerivativeContractTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DerivativeInstrumentsGainLossByDerivativeInstrumentRiskAxis" xlink:to="DerivativeContractTypeDomain_2" xlink:title="definition: DerivativeInstrumentsGainLossByDerivativeInstrumentRiskAxis to DerivativeContractTypeDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:to="DerivativeInstrumentsGainLossByDerivativeInstrumentRiskAxis" xlink:title="definition: DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable to DerivativeInstrumentsGainLossByDerivativeInstrumentRiskAxis" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QuestarPipelineMember" xlink:label="QuestarPipelineMember" xlink:title="QuestarPipelineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="QuestarPipelineMember" xlink:title="definition: EntityDomain to QuestarPipelineMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain_2" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LegalEntityAxis" xlink:to="EntityDomain_2" xlink:title="definition: LegalEntityAxis to EntityDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:to="LegalEntityAxis" xlink:title="definition: DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable to LegalEntityAxis" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesAssetAndLiabilityDerivativeInstrumentsDesignatedAsHedgesInBalanceSheetsDetails">
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativesFairValueLineItems" xlink:label="DerivativesFairValueLineItems" xlink:title="DerivativesFairValueLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset" xlink:label="DerivativeFairValueOfDerivativeAsset" xlink:title="DerivativeFairValueOfDerivativeAsset" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativesFairValueLineItems" xlink:to="DerivativeFairValueOfDerivativeAsset" xlink:title="definition: DerivativesFairValueLineItems to DerivativeFairValueOfDerivativeAsset" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:label="DerivativeFairValueOfDerivativeLiability" xlink:title="DerivativeFairValueOfDerivativeLiability" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativesFairValueLineItems" xlink:to="DerivativeFairValueOfDerivativeLiability" xlink:title="definition: DerivativesFairValueLineItems to DerivativeFairValueOfDerivativeLiability" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="DerivativeLineItems" xlink:title="DerivativeLineItems" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_AdditionalInformationAbstract" xlink:label="AdditionalInformationAbstract" xlink:title="AdditionalInformationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="AdditionalInformationAbstract" xlink:title="definition: DerivativeLineItems to AdditionalInformationAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:label="FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:title="FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DerivativesFairValueLineItems" xlink:to="FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:title="definition: DerivativesFairValueLineItems to FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" order="1.0" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_HedgingRelationshipDomain" xlink:label="HedgingRelationshipDomain" xlink:title="HedgingRelationshipDomain" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CashFlowHedgingMember" xlink:label="CashFlowHedgingMember" xlink:title="CashFlowHedgingMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="HedgingRelationshipDomain" xlink:to="CashFlowHedgingMember" xlink:title="definition: HedgingRelationshipDomain to CashFlowHedgingMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_FairValueHedgingMember" xlink:label="FairValueHedgingMember" xlink:title="FairValueHedgingMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="HedgingRelationshipDomain" xlink:to="FairValueHedgingMember" xlink:title="definition: HedgingRelationshipDomain to FairValueHedgingMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:label="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:title="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:to="HedgingRelationshipDomain" xlink:title="definition: DerivativeInstrumentsGainLossByHedgingRelationshipAxis to HedgingRelationshipDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_HedgingRelationshipDomain" xlink:label="HedgingRelationshipDomain_2" xlink:title="HedgingRelationshipDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:to="HedgingRelationshipDomain_2" xlink:title="definition: DerivativeInstrumentsGainLossByHedgingRelationshipAxis to HedgingRelationshipDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:to="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:title="definition: FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable to DerivativeInstrumentsGainLossByHedgingRelationshipAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="BalanceSheetLocationDomain" xlink:title="BalanceSheetLocationDomain" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_PrepaidExpensesAndOtherMember" xlink:label="PrepaidExpensesAndOtherMember" xlink:title="PrepaidExpensesAndOtherMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BalanceSheetLocationDomain" xlink:to="PrepaidExpensesAndOtherMember" xlink:title="definition: BalanceSheetLocationDomain to PrepaidExpensesAndOtherMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_OtherNoncurrentAssetsMember" xlink:label="OtherNoncurrentAssetsMember" xlink:title="OtherNoncurrentAssetsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BalanceSheetLocationDomain" xlink:to="OtherNoncurrentAssetsMember" xlink:title="definition: BalanceSheetLocationDomain to OtherNoncurrentAssetsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_AccountsPayableAndAccruedExpensesMember" xlink:label="AccountsPayableAndAccruedExpensesMember" xlink:title="AccountsPayableAndAccruedExpensesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BalanceSheetLocationDomain" xlink:to="AccountsPayableAndAccruedExpensesMember" xlink:title="definition: BalanceSheetLocationDomain to AccountsPayableAndAccruedExpensesMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativesFairValueByBalanceSheetLocationAxis" xlink:label="DerivativesFairValueByBalanceSheetLocationAxis" xlink:title="DerivativesFairValueByBalanceSheetLocationAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DerivativesFairValueByBalanceSheetLocationAxis" xlink:to="BalanceSheetLocationDomain" xlink:title="definition: DerivativesFairValueByBalanceSheetLocationAxis to BalanceSheetLocationDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="BalanceSheetLocationDomain_2" xlink:title="BalanceSheetLocationDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DerivativesFairValueByBalanceSheetLocationAxis" xlink:to="BalanceSheetLocationDomain_2" xlink:title="definition: DerivativesFairValueByBalanceSheetLocationAxis to BalanceSheetLocationDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:to="DerivativesFairValueByBalanceSheetLocationAxis" xlink:title="definition: FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable to DerivativesFairValueByBalanceSheetLocationAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QuestarPipelineMember" xlink:label="QuestarPipelineMember" xlink:title="QuestarPipelineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="QuestarPipelineMember" xlink:title="definition: EntityDomain to QuestarPipelineMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain_2" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LegalEntityAxis" xlink:to="EntityDomain_2" xlink:title="definition: LegalEntityAxis to EntityDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:to="LegalEntityAxis" xlink:title="definition: FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable to LegalEntityAxis" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="DerivativeLineItems" xlink:title="DerivativeLineItems" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_MaturityDateDerivative" xlink:label="MaturityDateDerivative" xlink:title="MaturityDateDerivative" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="MaturityDateDerivative" xlink:title="definition: DerivativeLineItems to MaturityDateDerivative" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeAverageFixedInterestRate" xlink:label="DerivativeAverageFixedInterestRate" xlink:title="DerivativeAverageFixedInterestRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="DerivativeAverageFixedInterestRate" xlink:title="definition: DerivativeLineItems to DerivativeAverageFixedInterestRate" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/invest-2009-01-31.xsd#invest_DerivativeNotionalAmount" xlink:label="DerivativeNotionalAmount" xlink:title="DerivativeNotionalAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="DerivativeNotionalAmount" xlink:title="definition: DerivativeLineItems to DerivativeNotionalAmount" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_InterestPaymentForTerminatedSwaps" xlink:label="InterestPaymentForTerminatedSwaps" xlink:title="InterestPaymentForTerminatedSwaps" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="InterestPaymentForTerminatedSwaps" xlink:title="definition: DerivativeLineItems to InterestPaymentForTerminatedSwaps" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_FixedInterestRateOnTerminatedDerivativeInstrument" xlink:label="FixedInterestRateOnTerminatedDerivativeInstrument" xlink:title="FixedInterestRateOnTerminatedDerivativeInstrument" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="FixedInterestRateOnTerminatedDerivativeInstrument" xlink:title="definition: DerivativeLineItems to FixedInterestRateOnTerminatedDerivativeInstrument" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ReclassificationFromAccumulatedOciToIncomeEstimatedTimeToTransfer" xlink:label="ReclassificationFromAccumulatedOciToIncomeEstimatedTimeToTransfer" xlink:title="ReclassificationFromAccumulatedOciToIncomeEstimatedTimeToTransfer" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="ReclassificationFromAccumulatedOciToIncomeEstimatedTimeToTransfer" xlink:title="definition: DerivativeLineItems to ReclassificationFromAccumulatedOciToIncomeEstimatedTimeToTransfer" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_PreTaxNetLossesGainExpectedToBeReclassifiedFromAociToConsolidatedStatementOfIncome" xlink:label="PreTaxNetLossesGainExpectedToBeReclassifiedFromAociToConsolidatedStatementOfIncome" xlink:title="PreTaxNetLossesGainExpectedToBeReclassifiedFromAociToConsolidatedStatementOfIncome" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="PreTaxNetLossesGainExpectedToBeReclassifiedFromAociToConsolidatedStatementOfIncome" xlink:title="definition: DerivativeLineItems to PreTaxNetLossesGainExpectedToBeReclassifiedFromAociToConsolidatedStatementOfIncome" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeTable" xlink:label="DerivativeTable" xlink:title="DerivativeTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DerivativeLineItems" xlink:to="DerivativeTable" xlink:title="definition: DerivativeLineItems to DerivativeTable" order="1.0" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_HedgingRelationshipDomain" xlink:label="HedgingRelationshipDomain" xlink:title="HedgingRelationshipDomain" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_CashFlowHedgingMember" xlink:label="CashFlowHedgingMember" xlink:title="CashFlowHedgingMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="HedgingRelationshipDomain" xlink:to="CashFlowHedgingMember" xlink:title="definition: HedgingRelationshipDomain to CashFlowHedgingMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_FairValueHedgingMember" xlink:label="FairValueHedgingMember" xlink:title="FairValueHedgingMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="HedgingRelationshipDomain" xlink:to="FairValueHedgingMember" xlink:title="definition: HedgingRelationshipDomain to FairValueHedgingMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:label="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:title="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:to="HedgingRelationshipDomain" xlink:title="definition: DerivativeInstrumentsGainLossByHedgingRelationshipAxis to HedgingRelationshipDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_HedgingRelationshipDomain" xlink:label="HedgingRelationshipDomain_2" xlink:title="HedgingRelationshipDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:to="HedgingRelationshipDomain_2" xlink:title="definition: DerivativeInstrumentsGainLossByHedgingRelationshipAxis to HedgingRelationshipDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DerivativeTable" xlink:to="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:title="definition: DerivativeTable to DerivativeInstrumentsGainLossByHedgingRelationshipAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeNameDomain" xlink:label="DerivativeNameDomain" xlink:title="DerivativeNameDomain" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ForwardContractsMember" xlink:label="ForwardContractsMember" xlink:title="ForwardContractsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeNameDomain" xlink:to="ForwardContractsMember" xlink:title="definition: DerivativeNameDomain to ForwardContractsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_SwapMember" xlink:label="SwapMember" xlink:title="SwapMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeNameDomain" xlink:to="SwapMember" xlink:title="definition: DerivativeNameDomain to SwapMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_NewForwardStartingInterestRateSwapsMember" xlink:label="NewForwardStartingInterestRateSwapsMember" xlink:title="NewForwardStartingInterestRateSwapsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeNameDomain" xlink:to="NewForwardStartingInterestRateSwapsMember" xlink:title="definition: DerivativeNameDomain to NewForwardStartingInterestRateSwapsMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeByNatureAxis" xlink:label="DerivativeByNatureAxis" xlink:title="DerivativeByNatureAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DerivativeByNatureAxis" xlink:to="DerivativeNameDomain" xlink:title="definition: DerivativeByNatureAxis to DerivativeNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DerivativeNameDomain" xlink:label="DerivativeNameDomain_2" xlink:title="DerivativeNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DerivativeByNatureAxis" xlink:to="DerivativeNameDomain_2" xlink:title="definition: DerivativeByNatureAxis to DerivativeNameDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DerivativeTable" xlink:to="DerivativeByNatureAxis" xlink:title="definition: DerivativeTable to DerivativeByNatureAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QuestarPipelineMember" xlink:label="QuestarPipelineMember" xlink:title="QuestarPipelineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="QuestarPipelineMember" xlink:title="definition: EntityDomain to QuestarPipelineMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/non-gaap/dei-2009-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain_2" xlink:title="EntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LegalEntityAxis" xlink:to="EntityDomain_2" xlink:title="definition: LegalEntityAxis to EntityDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DerivativeTable" xlink:to="LegalEntityAxis" xlink:title="definition: DerivativeTable to LegalEntityAxis" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/DerivativeInstrumentsAndHedgingActivitiesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/ShareBasedCompensation" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/ShareBasedCompensationDetails">
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_NumberOfRestrictedStockUnitsIssued" xlink:label="NumberOfRestrictedStockUnitsIssued" xlink:title="NumberOfRestrictedStockUnitsIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="NumberOfRestrictedStockUnitsIssued" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to NumberOfRestrictedStockUnitsIssued" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_WeightedAveragePriceOfRestrictedStockUnitsIssued" xlink:label="WeightedAveragePriceOfRestrictedStockUnitsIssued" xlink:title="WeightedAveragePriceOfRestrictedStockUnitsIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="WeightedAveragePriceOfRestrictedStockUnitsIssued" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to WeightedAveragePriceOfRestrictedStockUnitsIssued" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_WeightedAverageVestingPeriodOfRestrictedStockUnitsIssued" xlink:label="WeightedAverageVestingPeriodOfRestrictedStockUnitsIssued" xlink:title="WeightedAverageVestingPeriodOfRestrictedStockUnitsIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="WeightedAverageVestingPeriodOfRestrictedStockUnitsIssued" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to WeightedAverageVestingPeriodOfRestrictedStockUnitsIssued" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfYearsOfAwardIsSubjectToAdjustment" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfYearsOfAwardIsSubjectToAdjustment" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfYearsOfAwardIsSubjectToAdjustment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfYearsOfAwardIsSubjectToAdjustment" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfYearsOfAwardIsSubjectToAdjustment" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_TheDateShareBasedAwardWillBeDistributed" xlink:label="TheDateShareBasedAwardWillBeDistributed" xlink:title="TheDateShareBasedAwardWillBeDistributed" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="TheDateShareBasedAwardWillBeDistributed" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to TheDateShareBasedAwardWillBeDistributed" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardCompensationCost" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardCompensationCost" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardCompensationCost" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardCompensationCost" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardCompensationCost" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesMinimumPrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesMinimumPrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesMinimumPrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesMinimumPrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesMinimumPrice" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesMaximumPrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesMaximumPrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesMaximumPrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesMaximumPrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardUnvestedRestrictedSharesMaximumPrice" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationUnvestedRestrictedSharesGrantsInPeriodMinimumPrice" xlink:label="ShareBasedCompensationUnvestedRestrictedSharesGrantsInPeriodMinimumPrice" xlink:title="ShareBasedCompensationUnvestedRestrictedSharesGrantsInPeriodMinimumPrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationUnvestedRestrictedSharesGrantsInPeriodMinimumPrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationUnvestedRestrictedSharesGrantsInPeriodMinimumPrice" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationUnvestedRestrictedSharesGrantsInPeriodMaximumPrice" xlink:label="ShareBasedCompensationUnvestedRestrictedSharesGrantsInPeriodMaximumPrice" xlink:title="ShareBasedCompensationUnvestedRestrictedSharesGrantsInPeriodMaximumPrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationUnvestedRestrictedSharesGrantsInPeriodMaximumPrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationUnvestedRestrictedSharesGrantsInPeriodMaximumPrice" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationUnvestedRestrictedSharesVestedInPeriodMinimumPrice" xlink:label="ShareBasedCompensationUnvestedRestrictedSharesVestedInPeriodMinimumPrice" xlink:title="ShareBasedCompensationUnvestedRestrictedSharesVestedInPeriodMinimumPrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationUnvestedRestrictedSharesVestedInPeriodMinimumPrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationUnvestedRestrictedSharesVestedInPeriodMinimumPrice" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationUnvestedRestrictedSharesVestedInPeriodMaximumPrice" xlink:label="ShareBasedCompensationUnvestedRestrictedSharesVestedInPeriodMaximumPrice" xlink:title="ShareBasedCompensationUnvestedRestrictedSharesVestedInPeriodMaximumPrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationUnvestedRestrictedSharesVestedInPeriodMaximumPrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationUnvestedRestrictedSharesVestedInPeriodMaximumPrice" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationUnvestedRestrictedSharesForfeitedInPeriodMinimumPrice" xlink:label="ShareBasedCompensationUnvestedRestrictedSharesForfeitedInPeriodMinimumPrice" xlink:title="ShareBasedCompensationUnvestedRestrictedSharesForfeitedInPeriodMinimumPrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationUnvestedRestrictedSharesForfeitedInPeriodMinimumPrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationUnvestedRestrictedSharesForfeitedInPeriodMinimumPrice" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationUnvestedRestrictedSharesForfeitedInPeriodMaximumPrice" xlink:label="ShareBasedCompensationUnvestedRestrictedSharesForfeitedInPeriodMaximumPrice" xlink:title="ShareBasedCompensationUnvestedRestrictedSharesForfeitedInPeriodMaximumPrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationUnvestedRestrictedSharesForfeitedInPeriodMaximumPrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationUnvestedRestrictedSharesForfeitedInPeriodMaximumPrice" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredToEquityMethodInvesteeWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredToEquityMethodInvesteeWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredToEquityMethodInvesteeWeightedAverageGrantDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredToEquityMethodInvesteeWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredToEquityMethodInvesteeWeightedAverageGrantDateFairValue" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredToEquityMethodInvesteeWeightedAverageForfeitedDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredToEquityMethodInvesteeWeightedAverageForfeitedDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredToEquityMethodInvesteeWeightedAverageForfeitedDateFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredToEquityMethodInvesteeWeightedAverageForfeitedDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTransferredToEquityMethodInvesteeWeightedAverageForfeitedDateFairValue" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMinimumExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMinimumExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMinimumExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMinimumExercisePrice" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMinimumExercisePrice" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMaximumExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMaximumExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMaximumExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMaximumExercisePrice" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingMaximumExercisePrice" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedNumber" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedNumber" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedWeightedAverageExercisePrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedWeightedAverageExercisePrice" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="1.0" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_PerformanceSharesMember" xlink:label="PerformanceSharesMember" xlink:title="PerformanceSharesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="PerformanceSharesMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to PerformanceSharesMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_RestrictedSharesMember" xlink:label="RestrictedSharesMember" xlink:title="RestrictedSharesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="RestrictedSharesMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to RestrictedSharesMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_RestrictedStockUnitsMember" xlink:label="RestrictedStockUnitsMember" xlink:title="RestrictedStockUnitsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="RestrictedStockUnitsMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to RestrictedStockUnitsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:label="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:title="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:label="ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:title="ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems to ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" order="1.0" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_OptionsOutstandingExercisePriceRange1Member" xlink:label="OptionsOutstandingExercisePriceRange1Member" xlink:title="OptionsOutstandingExercisePriceRange1Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:to="OptionsOutstandingExercisePriceRange1Member" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain to OptionsOutstandingExercisePriceRange1Member" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_OptionsOutstandingExercisePriceRange2Member" xlink:label="OptionsOutstandingExercisePriceRange2Member" xlink:title="OptionsOutstandingExercisePriceRange2Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:to="OptionsOutstandingExercisePriceRange2Member" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain to OptionsOutstandingExercisePriceRange2Member" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_OptionsOutstandingExercisePriceRange3Member" xlink:label="OptionsOutstandingExercisePriceRange3Member" xlink:title="OptionsOutstandingExercisePriceRange3Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:to="OptionsOutstandingExercisePriceRange3Member" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain to OptionsOutstandingExercisePriceRange3Member" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:to="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis to ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_2" xlink:title="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:to="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_2" xlink:title="definition: ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis to ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:to="ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable to ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/ShareBasedCompensationTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/OperationsByLineOfBusiness" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/OperationsByLineOfBusinessDetails">
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="SegmentReportingInformationLineItems" xlink:title="SegmentReportingInformationLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_SegmentReportingInformationRevenueFromExternalCustomers" xlink:label="SegmentReportingInformationRevenueFromExternalCustomers" xlink:title="SegmentReportingInformationRevenueFromExternalCustomers" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentReportingInformationLineItems" xlink:to="SegmentReportingInformationRevenueFromExternalCustomers" xlink:title="definition: SegmentReportingInformationLineItems to SegmentReportingInformationRevenueFromExternalCustomers" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_SegmentReportingInformationIntersegmentRevenue" xlink:label="SegmentReportingInformationIntersegmentRevenue" xlink:title="SegmentReportingInformationIntersegmentRevenue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentReportingInformationLineItems" xlink:to="SegmentReportingInformationIntersegmentRevenue" xlink:title="definition: SegmentReportingInformationLineItems to SegmentReportingInformationIntersegmentRevenue" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="OperatingIncomeLoss" xlink:title="OperatingIncomeLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentReportingInformationLineItems" xlink:to="OperatingIncomeLoss" xlink:title="definition: SegmentReportingInformationLineItems to OperatingIncomeLoss" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromContinuingOperations" xlink:label="IncomeLossFromContinuingOperations" xlink:title="IncomeLossFromContinuingOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentReportingInformationLineItems" xlink:to="IncomeLossFromContinuingOperations" xlink:title="definition: SegmentReportingInformationLineItems to IncomeLossFromContinuingOperations" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="ScheduleOfSegmentReportingInformationBySegmentTable" xlink:title="ScheduleOfSegmentReportingInformationBySegmentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="SegmentReportingInformationLineItems" xlink:to="ScheduleOfSegmentReportingInformationBySegmentTable" xlink:title="definition: SegmentReportingInformationLineItems to ScheduleOfSegmentReportingInformationBySegmentTable" order="1.0" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ReportingSegmentDomain" xlink:label="ReportingSegmentDomain" xlink:title="ReportingSegmentDomain" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_CorporateMember" xlink:label="CorporateMember" xlink:title="CorporateMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ReportingSegmentDomain" xlink:to="CorporateMember" xlink:title="definition: ReportingSegmentDomain to CorporateMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QuestarGasMember" xlink:label="QuestarGasMember" xlink:title="QuestarGasMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ReportingSegmentDomain" xlink:to="QuestarGasMember" xlink:title="definition: ReportingSegmentDomain to QuestarGasMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QuestarPipelineMember" xlink:label="QuestarPipelineMember" xlink:title="QuestarPipelineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ReportingSegmentDomain" xlink:to="QuestarPipelineMember" xlink:title="definition: ReportingSegmentDomain to QuestarPipelineMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_WexproMember" xlink:label="WexproMember" xlink:title="WexproMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ReportingSegmentDomain" xlink:to="WexproMember" xlink:title="definition: ReportingSegmentDomain to WexproMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_SegmentReportingInformationBySegmentAxis" xlink:label="SegmentReportingInformationBySegmentAxis" xlink:title="SegmentReportingInformationBySegmentAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SegmentReportingInformationBySegmentAxis" xlink:to="ReportingSegmentDomain" xlink:title="definition: SegmentReportingInformationBySegmentAxis to ReportingSegmentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ReportingSegmentDomain" xlink:label="ReportingSegmentDomain_2" xlink:title="ReportingSegmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SegmentReportingInformationBySegmentAxis" xlink:to="ReportingSegmentDomain_2" xlink:title="definition: SegmentReportingInformationBySegmentAxis to ReportingSegmentDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="SegmentReportingInformationBySegmentAxis" xlink:title="definition: ScheduleOfSegmentReportingInformationBySegmentTable to SegmentReportingInformationBySegmentAxis" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/OperationsByLineOfBusinessTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/EmployeeBenefits" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/EmployeeBenefitsDetails">
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:label="DefinedBenefitPlanDisclosureLineItems" xlink:title="DefinedBenefitPlanDisclosureLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost" xlink:label="DefinedBenefitPlanServiceCost" xlink:title="DefinedBenefitPlanServiceCost" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedBenefitPlanDisclosureLineItems" xlink:to="DefinedBenefitPlanServiceCost" xlink:title="definition: DefinedBenefitPlanDisclosureLineItems to DefinedBenefitPlanServiceCost" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost" xlink:label="DefinedBenefitPlanInterestCost" xlink:title="DefinedBenefitPlanInterestCost" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedBenefitPlanDisclosureLineItems" xlink:to="DefinedBenefitPlanInterestCost" xlink:title="definition: DefinedBenefitPlanDisclosureLineItems to DefinedBenefitPlanInterestCost" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:label="DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:title="DefinedBenefitPlanExpectedReturnOnPlanAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedBenefitPlanDisclosureLineItems" xlink:to="DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:title="definition: DefinedBenefitPlanDisclosureLineItems to DefinedBenefitPlanExpectedReturnOnPlanAssets" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfTransitionObligationsAssets" xlink:label="DefinedBenefitPlanAmortizationOfTransitionObligationsAssets" xlink:title="DefinedBenefitPlanAmortizationOfTransitionObligationsAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedBenefitPlanDisclosureLineItems" xlink:to="DefinedBenefitPlanAmortizationOfTransitionObligationsAssets" xlink:title="definition: DefinedBenefitPlanDisclosureLineItems to DefinedBenefitPlanAmortizationOfTransitionObligationsAssets" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses" xlink:label="DefinedBenefitPlanAmortizationOfGainsLosses" xlink:title="DefinedBenefitPlanAmortizationOfGainsLosses" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedBenefitPlanDisclosureLineItems" xlink:to="DefinedBenefitPlanAmortizationOfGainsLosses" xlink:title="definition: DefinedBenefitPlanDisclosureLineItems to DefinedBenefitPlanAmortizationOfGainsLosses" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:label="DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:title="DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedBenefitPlanDisclosureLineItems" xlink:to="DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:title="definition: DefinedBenefitPlanDisclosureLineItems to DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DefinedBenefitPlanActuarialNetGainsLosses" xlink:label="DefinedBenefitPlanActuarialNetGainsLosses" xlink:title="DefinedBenefitPlanActuarialNetGainsLosses" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedBenefitPlanDisclosureLineItems" xlink:to="DefinedBenefitPlanActuarialNetGainsLosses" xlink:title="definition: DefinedBenefitPlanDisclosureLineItems to DefinedBenefitPlanActuarialNetGainsLosses" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DefinedBenefitPlanCurtailments" xlink:label="DefinedBenefitPlanCurtailments" xlink:title="DefinedBenefitPlanCurtailments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedBenefitPlanDisclosureLineItems" xlink:to="DefinedBenefitPlanCurtailments" xlink:title="definition: DefinedBenefitPlanDisclosureLineItems to DefinedBenefitPlanCurtailments" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_AccretionOfRegulatoryLiability" xlink:label="AccretionOfRegulatoryLiability" xlink:title="AccretionOfRegulatoryLiability" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedBenefitPlanDisclosureLineItems" xlink:to="AccretionOfRegulatoryLiability" xlink:title="definition: DefinedBenefitPlanDisclosureLineItems to AccretionOfRegulatoryLiability" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DefinedBenefitPlanSpecialTerminationBenefits" xlink:label="DefinedBenefitPlanSpecialTerminationBenefits" xlink:title="DefinedBenefitPlanSpecialTerminationBenefits" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedBenefitPlanDisclosureLineItems" xlink:to="DefinedBenefitPlanSpecialTerminationBenefits" xlink:title="definition: DefinedBenefitPlanDisclosureLineItems to DefinedBenefitPlanSpecialTerminationBenefits" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:label="DefinedBenefitPlanNetPeriodicBenefitCost" xlink:title="DefinedBenefitPlanNetPeriodicBenefitCost" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedBenefitPlanDisclosureLineItems" xlink:to="DefinedBenefitPlanNetPeriodicBenefitCost" xlink:title="definition: DefinedBenefitPlanDisclosureLineItems to DefinedBenefitPlanNetPeriodicBenefitCost" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:label="ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:title="ScheduleOfDefinedBenefitPlansDisclosuresTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DefinedBenefitPlanDisclosureLineItems" xlink:to="ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:title="definition: DefinedBenefitPlanDisclosureLineItems to ScheduleOfDefinedBenefitPlansDisclosuresTable" order="1.0" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DefinedBenefitPlansDomain" xlink:label="DefinedBenefitPlansDomain" xlink:title="DefinedBenefitPlansDomain" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember" xlink:label="UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember" xlink:title="UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedBenefitPlansDomain" xlink:to="UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember" xlink:title="definition: DefinedBenefitPlansDomain to UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember" xlink:label="UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember" xlink:title="UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefinedBenefitPlansDomain" xlink:to="UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember" xlink:title="definition: DefinedBenefitPlansDomain to UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis" xlink:label="DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis" xlink:title="DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis" xlink:to="DefinedBenefitPlansDomain" xlink:title="definition: DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis to DefinedBenefitPlansDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DefinedBenefitPlansDomain" xlink:label="DefinedBenefitPlansDomain_2" xlink:title="DefinedBenefitPlansDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis" xlink:to="DefinedBenefitPlansDomain_2" xlink:title="definition: DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis to DefinedBenefitPlansDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:to="DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis" xlink:title="definition: ScheduleOfDefinedBenefitPlansDisclosuresTable to DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/EmployeeBenefitsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/DiscontinuedOperations" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/DiscontinuedOperationsDetails">
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:label="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:title="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue" xlink:label="DisposalGroupIncludingDiscontinuedOperationRevenue" xlink:title="DisposalGroupIncludingDiscontinuedOperationRevenue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="DisposalGroupIncludingDiscontinuedOperationRevenue" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to DisposalGroupIncludingDiscontinuedOperationRevenue" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_DisposalGroupIncludingDiscontinuedOperationSeveranceCosts" xlink:label="DisposalGroupIncludingDiscontinuedOperationSeveranceCosts" xlink:title="DisposalGroupIncludingDiscontinuedOperationSeveranceCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="DisposalGroupIncludingDiscontinuedOperationSeveranceCosts" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to DisposalGroupIncludingDiscontinuedOperationSeveranceCosts" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax" xlink:label="DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax" xlink:title="DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to IncomeLossFromDiscontinuedOperationsNetOfTax" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" xlink:label="IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" xlink:title="IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:label="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:title="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems to IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" order="1.0" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:title="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" />
    <link:loc xlink:type="locator" xlink:href="str-20110930.xsd#str_QepOperationsMember" xlink:label="QepOperationsMember" xlink:title="QepOperationsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:to="QepOperationsMember" xlink:title="definition: DisposalGroupsIncludingDiscontinuedOperationsNameDomain to QepOperationsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:title="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:to="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis to DisposalGroupsIncludingDiscontinuedOperationsNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="http://taxonomies.xbrl.us/us-gaap/2009/elts/us-gaap-2009-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2" xlink:title="DisposalGroupsIncludingDiscontinuedOperationsNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:to="DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis to DisposalGroupsIncludingDiscontinuedOperationsNameDomain_2" priority="1" order="2.0" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:to="IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:title="definition: IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable to IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/DiscontinuedOperationsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/RecentAccountingDevelopment" />
  <link:definitionLink xlink:type="extended" xlink:role="http://questar.com/role/DocumentAndEntityInformation" />
</link:linkbase>
