X0306 4 2012-08-01 0 0000882095 GILEAD SCIENCES INC GILD 0001334682 Alton Gregg H GILEAD SCIENCES, INC. 333 LAKESIDE DRIVE FOSTER CITY CA 94404 0 1 0 0 EVP, Corp & Med Affairs Common Stock 2012-08-01 4 M 0 11000 21.985 A 50790 D Common Stock 2012-08-01 4 S 0 12000 54.0833 D 38790 D Common Stock 2012-08-02 4 M 0 31371 21.985 A 70161 D Common Stock 2012-08-02 4 S 0 31371 57.9475 D 38790 D Common Stock 2012-08-02 4 M 0 21629 29.005 A 60419 D Common Stock 2012-08-02 4 S 0 21629 57.9475 D 38790 D Common Stock 2012-08-02 4 M 0 7000 19.36 A 45790 D Common Stock 2012-08-02 4 S 0 7000 57.9475 D 38790 D Non-Qualified Stock Option (right to buy) 19.36 2012-08-02 4 M 0 7000 0 D 2015-05-09 Common Stock 7000 0 D Non-Qualified Stock Option (right to buy) 21.985 2012-08-01 4 M 0 11000 0 D 2015-07-27 Common Stock 11000 31371 D Non-Qualified Stock Option (right to buy) 21.985 2012-08-02 4 M 0 31371 0 D 2015-07-27 Common Stock 31371 0 D Non-Qualified Stock Option (right to buy) 29.005 2012-08-02 4 M 0 21629 0 D 2016-01-25 Common Stock 21629 128371 D The exercise and sale transactions reported in this Form 4 made pursuant to a Rule 10b5-1 trading plan established by Mr. Alton on February 7, 2012. The options have a five year vesting schedule. 20% vest on the first anniversary of the date of grant. The balance will vest 5% quarterly thereafter until fully vested. Sale prices reported for the transactions reported here range from $53.60 to $54.50. Full information regarding the number of shares purchased or sold at each separate price will be provided to the SEC, the issuer or its shareowners upon request. Sale prices reported for the transactions reported here range from $57.59 to $58.03. Full information regarding the number of shares purchased or sold at each separate price will be provided to the SEC, the issuer or its shareowners upon request. /s/ Kristen M. Metza by Power of Attorney for Gregg H. Alton 2012-08-03