Statement of Changes of Beneficial Ownership

FORM 4
[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).         
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES
                                                                                  
OMB APPROVAL
OMB Number: 3235-0287
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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public
Utility Holding Company Act of 1935 or Section 30(f) of the Investment Company Act of 1940
                      

1. Name and Address of Reporting Person *

REINHARD J PEDRO 		2. Issuer Name and Ticker or Trading Symbol

SIGMA ALDRICH CORP [ SIAL ] 		5. Relationship of Reporting Person(s) to Issuer (Check all applicable)

__ X __ Director                      _____ 10% Owner
_____ Officer (give title below)      _____ Other (specify below)
(Last)          (First)          (Middle)

3050 SPRUCE STREET 		3. Date of Earliest Transaction (MM/DD/YYYY)

5/2/2012
(Street)

ST. LOUIS, MO 63103
(City)        (State)        (Zip)
4. If Amendment, Date Original Filed (MM/DD/YYYY)

 
6. Individual or Joint/Group Filing (Check Applicable Line)

_ X _ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3) 		2. Trans. Date 2A. Deemed Execution Date, if any 3. Trans. Code
(Instr. 8) 		4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5) 		5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4) 		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V Amount (A) or (D) Price

Table II - Derivative Securities Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security
(Instr. 3) 		2. Conversion or Exercise Price of Derivative Security 3. Trans. Date 3A. Deemed Execution Date, if any 4. Trans. Code
(Instr. 8) 		5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5) 		6. Date Exercisable and Expiration Date 7. Title and Amount of Securities Underlying Derivative Security
(Instr. 3 and 4) 		8. Price of Derivative Security
(Instr. 5) 		9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
NQ Stock Option, Right to Buy   $71.1   5/2/2012     A      10000       8/2/2012   5/2/2022   Common Stock   10000   $0   10000   D    

Explanation of Responses:

Reporting Owners
Reporting Owner Name / Address
Relationships
Director 10% Owner Officer Other
REINHARD J PEDRO
3050 SPRUCE STREET
ST. LOUIS, MO 63103 		X



Signatures
Jesica Betts, Attorney in Fact 5/5/2012
** Signature of Reporting Person Date


Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.

Power of Attorney

Know all by these presents, that the undersigned (the "Reporting Person"), in connection with the Reporting Person's beneficial ownership of Sigma-Aldrich Corporation (the "Company") securities, hereby constitutes and appoints each of Barbara Branchfield, Kimberly Reno or Jesica Betts, or any of them signing singly and with full power of substitution, to act as the Reporting Person's true and lawful attorney-in-fact to:

* execute for and on behalf of the Reporting Person Forms 3, 4 and 5 in accordance with Section 16(a) of the Securities Exchange Act of 1934 (the "Exchange Act") and the rules thereunder;

* do and perform and all acts for and on behalf of the Reporting Person which may be necessary or desirable to complete and execute any such Forms 3, 4 or 5 and timely file such forms with the United States Securities and Exchange Commission and any stock exchange or similar authority; and

* take any other action of any type whatsoever in connection with the foregoing, which in the opinion of such attorney- in-fact, may be of benefit to, and in the best interest of, or legally required by, the Reporting Person.

The Reporting Person acknowledges that the foregoing attorneys- in-fact, in serving in such capacity at the request of the Reporting Person, are not assuming, nor is the Company assuming, any of the Reporting Persons responsibilities to comply with
Section 16 of the Exchange Act.

This Power of Attorney shall remain in full force and effect until the Reporting Person is no longer required to file Forms 3, 4 and 5 with respect to the Reporting Person's holdings of, and transactions in, securities issued by the Company, unless earlier revoked by the Reporting Person in a signed writing delivered to the foregoing attorney-in-fact.

IN WITNESS WHEREOF, the Reporting Person has caused this Power of Attorney to be executed as of this 5th day of January, 2012. 

/s/ J. Pedro Reinhard
Signature

Reporting Person:  J. Pedro Reinhard
delivered to the foregoing attorney-in-fact.

IN WITNESS WHEREOF, the Reporting Person has caused this Power of Attorney to be executed as of this 5th day of January, 2012. 

/s/ J. Pedro Reinhard
Signature

Reporting Person:  J. Ped