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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 D8+22I1IRNqgxOGTT3lwi6Tan28KsRiKqmMQlV8AdDOp5yzrAGqVYpxklLRADgdR
 0vjRk/TlItsg2bF3Y4fW1A==

<SEC-DOCUMENT>0001179110-03-006703.txt : 20030902
<SEC-HEADER>0001179110-03-006703.hdr.sgml : 20030901
<ACCEPTANCE-DATETIME>20030902190625
ACCESSION NUMBER:		0001179110-03-006703
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030829
FILED AS OF DATE:		20030902

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			GILEAD SCIENCES INC
		CENTRAL INDEX KEY:			0000882095
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		IRS NUMBER:				943047598
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		333 LAKESIDE DR
		CITY:			FOSTER CITY
		STATE:			CA
		ZIP:			94404
		BUSINESS PHONE:		6505743000

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LEE WILLIAM A
		CENTRAL INDEX KEY:			0001191592

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-19731
		FILM NUMBER:		03877325

	BUSINESS ADDRESS:	
		STREET 1:		GILEAD SCIENCES, INC.
		STREET 2:		333 LAKESIDE DRIVE
		CITY:			FOSTER CITY
		STATE:			CA
		ZIP:			94404
		BUSINESS PHONE:		6505743000

	MAIL ADDRESS:	
		STREET 1:		GILEAD SCIENCES, INC.
		STREET 2:		333 LAKESIDE DRIVE
		CITY:			FOSTER CITY
		STATE:			CA
		ZIP:			94404
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
<periodOfReport>2003-08-29</periodOfReport>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000882095</issuerCik>
        <issuerName>GILEAD SCIENCES INC</issuerName>
        <issuerTradingSymbol>GILD</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001191592</rptOwnerCik>
            <rptOwnerName>LEE WILLIAM A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>333 LAKESIDE DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>FOSTER CITY</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94404</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>1</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle>SVP Research and PPD</officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Common Stock</value>
</securityTitle>
<transactionDate><value>2003-08-29</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>M</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>15000</value>
</transactionShares>
<transactionPricePerShare><value>5.7188</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>76014</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</nonDerivativeTransaction>
<nonDerivativeTransaction><securityTitle><value>Common Stock</value>
</securityTitle>
<transactionDate><value>2003-08-29</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>S</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>15000</value>
</transactionShares>
<transactionPricePerShare><value>66.1000</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>61014</value>
<footnoteId id="F1"></footnoteId>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</nonDerivativeTransaction>
</nonDerivativeTable>
<derivativeTable><derivativeTransaction><securityTitle><value>Non-Qualified Stock Option (right to buy)</value>
</securityTitle>
<conversionOrExercisePrice><value>5.7188</value>
</conversionOrExercisePrice>
<transactionDate><value>2003-08-29</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>M</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>15000</value>
</transactionShares>
<transactionPricePerShare><value>0</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<exerciseDate><value>1999-07-23</value>
</exerciseDate>
<expirationDate><value>2008-07-23</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>15000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>9916</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeTransaction>
</derivativeTable>
<footnotes><footnote id="F1">All shares and dollar amounts reflect two-for-one stock splits in February 2001 and March 2002.</footnote>
</footnotes>
<ownerSignature><signatureName>/s/ WIlliam A. Lee</signatureName>
<signatureDate>2003-09-02</signatureDate>
</ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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