Initial Statement of Beneficial Ownership

FORM 3	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES	OMB APPROVAL OMB Number: 3235-0104 Expires: January 31, 2008 Estimated average burden hours per response... 0.5
	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(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person ^*
SKYLER JAY S
2. Date of Event Requiring Statement (MM/DD/YYYY) 4/13/2005
3. Issuer Name and Ticker or Trading Symbol
DEXCOM INC [DXCM]

(Last)        (First)        (Middle)
C/O DEXCOM, INC., 5555 OBERLIN DRIVE
4. Relationship of Reporting Person(s) to Issuer (Check all applicable)
__ X __ Director                                _____ 10% Owner
_____ Officer (give title below)                _____ Other (specify below)

(Street)
SAN DIEGO,CA 92121

(City)              (State)              (Zip) 5. 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 Beneficially Owned

1.Title of Security
(Instr. 4) 2. Amount of Securities Beneficially Owned
(Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5) 4. Nature of Indirect Beneficial Ownership
(Instr. 5)

Common Stock 62500 I By Trust ⁽¹⁾

Table II - Derivative Securities Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities)

1. Title of Derivate Security
(Instr. 4) 2. Date Exercisable and Expiration Date
(MM/DD/YYYY) 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4) 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5) 6. Nature of Indirect Beneficial Ownership
(Instr. 5)

Date Exercisable Expiration Date Title Amount or Number of Shares

Series D Preferred Stock ⁽²⁾ ⁽³⁾ Common Stock 18568 ⁽²⁾ I By Trust ⁽¹⁾

Explanation of Responses:

( 1) Shares are held by Jay S. Skyler Revocable Trust, which the Reporting Person is a Trustee.

( 2) Each share of preferred stock is convertible into 0.5 shares of the Issuers Common Stock and will convert automatically upon the closing of the Issuers initial public offering of Common Stock pursuant to an effective registration statement filed with the U.S. Securities and Exchange Commission.

( 3) Not Applicable

Remarks:
This Statement confirms that the undersigned, Dr. Jay S. Skyer, has authorized and designated Nooshin Hussainy to execute and file on the undersigned's behalf all Forms 3, 4, and 5 (including any amendments thereto) that the undersigned may be required to file with the U.S. Securities and Exchange Commission as a result of the undersigned's ownership of or transactions in securities of Dexcom, Inc. The authority of Nooshin Hussainy under this Statement shall continue until the undersigned is no longer required to file Forms 3, 4, and 5 with regard to the undersigned's ownership of or transactions in securities of Dexcom, Inc., unless earlier revoked in writing. The undersigned acknowledges that Nooshin Hussainy is not assuming any of the undersigned's responsibilities to comply with Section 16 of the Securities Exchange Act of 1934.
/s/Dr. Jay S. Skyler

Reporting Owners

Reporting Owner Name / Address Relationships

Director 10% Owner Officer Other

SKYLER JAY S
C/O DEXCOM, INC.
5555 OBERLIN DRIVE
SAN DIEGO, CA 92121 X

Signatures

Nooshin Hussainy on behalf of Dr. Jay S. Skyler 4/13/2005

^** 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 5(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.

Table I - Non-Derivative Securities Beneficially Owned
Common Stock	62500	I	By Trust ⁽¹⁾

*Table II - Derivative Securities Beneficially Owned ( e.g.* , puts, calls, warrants, options, convertible securities)**
Series D Preferred Stock	⁽²⁾	⁽³⁾	Common Stock	18568	⁽²⁾	I	By Trust ⁽¹⁾

End of Filing

Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	62500	I	By Trust ⁽¹⁾

*Table II - Derivative Securities Beneficially Owned ( e.g.* , puts, calls, warrants, options, convertible securities)**
1. Title of Derivate Security (Instr. 4)	2. Date Exercisable and Expiration Date (MM/DD/YYYY)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivate Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security		6. Nature of Indirect Beneficial Ownership (Instr. 5)
Series D Preferred Stock	⁽²⁾	⁽³⁾	Common Stock	18568	⁽²⁾	I	By Trust ⁽¹⁾

Explanation of Responses:
( 1)	Shares are held by Jay S. Skyler Revocable Trust, which the Reporting Person is a Trustee.
( 2)	Each share of preferred stock is convertible into 0.5 shares of the Issuers Common Stock and will convert automatically upon the closing of the Issuers initial public offering of Common Stock pursuant to an effective registration statement filed with the U.S. Securities and Exchange Commission.
( 3)	Not Applicable

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 5(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.