Power of Attorney

	Know all by these presents, that the undersigned hereby
constitutes and appoints each of John F. Milligan, Gregg H. Alton,
Robin L.Washington, Kristen M. Metza, Kevin Young and Brett A. Pletcher,
signing individually, the undersigned's true and lawful attorneys-
in-fact and agents to:

 (1) execute for and on behalf of the undersigned, an officer or
director of Gilead Sciences, Inc. (the "Company"), Forms 3, 4 and
5 in accordance with Section 16(a) of the Securities Exchange Act of
1934, as amended (the "Exchange Act") and the rules there under;

 (2) do and perform any and all acts for and on behalf of the undersigned
that may be necessary or desirable to complete and execute such Form 3, 4
or 5, complete and execute and amendment or amendments thereto, and timely
file such forms or amendments with United States Securities and Exchange
Commission and any stock exchange or similar authority; and

 (3) take any other action of any nature whatsoever in connection with the
foregoing which, in the opinion of such attorney-in-fact, may be of
benefit, in the best interest of, or legally required by, the
undersigned,it being understood that the documents executed by such
attorney-in-fact on behalf of the undersigned pursuant to this
Power of Attorney shall be in such form and shall contain such terms
and conditions as such attorney-in-fact may approve in such
attorney-in-fact's discretion.

       The undersigned hereby grants to each such attorney-in-fact full
power and authority to do and perform any and every act and thing
whatsoever requisite, necessary, or proper to be done in the exercise of
any of the rights and powers herein granted, fully to all intents and
purpose as the undersigned might or could do if personally present, with
full power of substitution or revocation, hereby ratifying and confirming
all that such attorney-in-fact, or such attorney-in-fact's substitute or
substitutes, shall lawfully do or cause to be done by virtue of this power
of attorney and the rights and powers herein granted. The undersigned
acknowledges that the foregoing attorneys-in-fact, in serving in such
capacity at the request of the undersigned, are not assuming, nor is the
Company assuming, any of the undersigned's responsibilities to comply
with Section 16 of the Exchange Act.

     This Power of Attorney shall remain in full force and effect
until the earliest to occur of (a) the undersigned is no longer required
to file Forms 3, 4 and 5 with respect to the undersigned's holdings of
and transactions in securities issued by the Company, (b) revocation by
the undersigned in a signed writing delivered to the foregoing
attorney's-in-fact or (c) as to any attorney-in-fact individually, until
such attorney-in-fact shall no longer be employed by the Company.

     IN WITNESS WHEREOF, the undersigned has caused this Power of
Attorney to be executed as of this 5th day of July, 2011.


/s/James M. Denny