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 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

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1. Name and Address of Reporting Person * Canaan Equity Partners II LLC   2. Issuer Name and Ticker or Trading Symbol DEXCOM INC [DXCM] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 105 ROWAYTON AVE,  3. Date of Earliest Transaction (Month/Day/Year) 04/19/2005 (Street) ROWAYTON, CT 06853 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction 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 Common Stock 04/19/2005   C   1,733,941 A (1) 1,733,941 I See Footnote (3) Common Stock 04/19/2005   C   1,079,075 A (1) 1,079,075 I See Footnote (4) Common Stock 04/19/2005   C   280,619 A (1) 280,619 I See Footnote (5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction 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 (Month/Day/Year)

7. Title and Amount of Underlying Securities (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

Series B Preferred Stock

(1)

04/19/2005

C

3,467,833

(1)

(2)

Common Stock

1,733,941 (1)

(1)

0

I

See Footnote (3)

Series C Preferred Stock

(1)

04/19/2005

C

2,158,152

(1)

(2)

Common Stock

1,079,075 (1)

(1)

0

I

See Footnote (4)

Series D Preferred Stock

(1)

04/19/2005

C

561,240

(1)

(2)

Common Stock

280,619 (1)

(1)

0

I

See Footnote (5)

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Canaan Equity Partners II LLC 105 ROWAYTON AVE ROWAYTON, CT 06853		X
CANAAN EQUITY II LP		X
Canaan Equity II, L.P. (QP) 105 ROWAYTON AVE ROWAYTON, CT 06853		X
CANAAN EQUITY II ENTREPRENEURS LLC		X
BALEN JOHN V		X
FURNIVALL JAMES C 193 BRANCH BROOK WILTON, CT 06897		X
GREEN L STEPHEN GREEN STEPHEN L 105 ROWAYTON AVE ROWAYTON, CT 06853		X
DEEPAK KAMRA DEEPAK KAMRA 105 ROWAYTON AVE ROWAYTON, CT 06853		X
KOPCHINSKY GREGORY 44 CLEARVIEW LANE NEW CANAAN, CT 06840		X
RUSSO GUY M 28 HORSESHOE RIDGE ROAD SANDY HOOK, CT 06482		X

Signatures

John D. Lambreck as Attorney in Fact		04/19/2005
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	Each share of the Series B, Series C and Series D Redeemable Convertible Preferred Stock converted automatically into 0.5 shares of Common Stock 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.
(2)	Not Applicable
(3)	Consists of 1,135,731 shares held by Canaan Equity II L.P.; 508,045 shares held by Canaan Equity II L.P. (QP) and 90,165 shares held by Canaan Equity II Entrepreneurs LLC. John Balen, Jim Furnivall, Steve Green, Deepak Kamra, Gregory Kopchinsky, Guy Russo, Eric Young, Charmers Landing LLC, Stonehenge LLC and Waubeeka LLC are Managers of Canaan Equity Partners II LLC, the General Partner or Manager of these funds, which individuals may be deemed to have shared voting, investment and dispositive power with respect to these shares, but disclaim beneficial ownership of all shares except to the extent of any pecuniary interest therein.
(4)	Consists of 706,794 shares held by Canaan Equity II L.P.; 316,169 shares held by Canaan Equity II L.P. (QP) and 56,112 shares held by Canaan Equity II Entrepreneurs LLC. John Balen, Jim Furnivall, Steve Green, Deepak Kamra, Gregory Kopchinsky, Guy Russo, Eric Young, Charmers Landing LLC, Stonehenge LLC and Waubeeka LLC are Managers of Canaan Equity Partners II LLC, the General Partner or Manager of these funds, which individuals may be deemed to have shared voting, investment and dispositive power with respect to these shares, but disclaim beneficial ownership of all shares except to the extent of any pecuniary interest therein.
(5)	Consists of 183,806 shares held by Canaan Equity II L.P.; 82,221 shares held by Canaan Equity II L.P. (QP) and 14,592 shares held by Canaan Equity II Entrepreneurs LLC. John Balen, Jim Furnivall, Steve Green, Deepak Kamra, Gregory Kopchinsky, Guy Russo, Eric Young, Charmers Landing LLC, Stonehenge LLC and Waubeeka LLC are Managers of Canaan Equity Partners II LLC, the General Partner or Manager of these funds, which individuals may be deemed to have shared voting, investment and dispositive power with respect to these shares, but disclaim beneficial ownership of all shares except to the extent of any pecuniary interest therein.
Remarks: This Form 4 is 1 of 2 filed in connection with a group joint filing consisting of a total of 14 group members (Canaan Equity Partners II LLC, Canaan Equity II L.P., Canaan Equity II L.P. (QP), Canaan Equity II Entrepreneurs LLC, John V. Balen, James C. Furnivall, Stephen L. Green, Deepak Kamra, Gregory Kopchinsky, Guy M. Russo, Eric A. Young, Charmers Landing LLC, Stonehenge, LLC and Waubeeka LLC) which Canaan Equity Partners II LLC is the designated filer.

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