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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 CQ8GAe2tCxdHextGAgaK0OUx6Mm4foawrVEm+YeX9AcQFD695jQ5E9pY7rRHOP5b
 V8QMaz9B32Y5qgPiWBNhAA==

<SEC-DOCUMENT>0001179110-03-005017.txt : 20030806
<SEC-HEADER>0001179110-03-005017.hdr.sgml : 20030806
<ACCEPTANCE-DATETIME>20030806155412
ACCESSION NUMBER:		0001179110-03-005017
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	19880808
FILED AS OF DATE:		20030806

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MASTERS CLARK H
		CENTRAL INDEX KEY:			0001242780

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-15086
		FILM NUMBER:		03826296

	MAIL ADDRESS:	
		STREET 1:		4150 NETWORK CIRCLE
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95054

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SUN MICROSYSTEMS INC
		CENTRAL INDEX KEY:			0000709519
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRONIC COMPUTERS [3571]
		IRS NUMBER:				942805249
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		4150 NETWORK CIRCLE
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95054
		BUSINESS PHONE:		6509601300

	MAIL ADDRESS:	
		STREET 1:		4150 NETWORK CIRCLE
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95054
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
<periodOfReport>1988-08-08</periodOfReport>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000709519</issuerCik>
        <issuerName>SUN MICROSYSTEMS INC</issuerName>
        <issuerTradingSymbol>sunw</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001242780</rptOwnerCik>
            <rptOwnerName>MASTERS CLARK H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>4150 NETWORK CIRCLE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SANTA CLARA</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95054</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>1</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle>Executive Vice President</officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Common Stock</value>
</securityTitle>
<transactionDate><value>2003-08-04</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>S</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>23255</value>
</transactionShares>
<transactionPricePerShare><value>3.74</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts><valueOwnedFollowingTransaction><value>24777</value>
</valueOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</nonDerivativeTransaction>
<nonDerivativeTransaction><securityTitle><value>Common Stock</value>
</securityTitle>
<transactionDate><value>2003-08-04</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>S</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>13455</value>
<footnoteId id="F1"></footnoteId>
</transactionShares>
<transactionPricePerShare><value>3.74</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership><value>By Wife</value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeTransaction>
<nonDerivativeTransaction><securityTitle><value>Common Stock</value>
</securityTitle>
<transactionDate><value>1988-08-08</value>
<footnoteId id="F2"></footnoteId>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>J</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
<footnoteId id="F3"></footnoteId>
</transactionCoding>
<transactionAmounts><transactionShares><value>0</value>
</transactionShares>
<transactionPricePerShare><value>0</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>24788</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership><value>By Trust</value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeTransaction>
<nonDerivativeTransaction><securityTitle><value>Common Stock</value>
</securityTitle>
<transactionDate><value>1988-08-08</value>
<footnoteId id="F2"></footnoteId>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>J</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
<footnoteId id="F3"></footnoteId>
</transactionCoding>
<transactionAmounts><transactionShares><value>0</value>
</transactionShares>
<transactionPricePerShare><value>0</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>460</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership><value>By Son, Kevin</value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeTransaction>
</nonDerivativeTable>
<derivativeTable></derivativeTable>
<footnotes><footnote id="F1">Reflects purchases under Sun Microsystems, Inc. 1990 Employee Stock Purchase Plan of 1,443 Shares on October 31, 2002, and 3,016 Shares on April 30, 2003.</footnote>
<footnote id="F2">In Section 16 Electronic Reporting Frequently Asked Questions released by the SEC on May 1, 2003, the SEC designated "08/08/1988" as a "dummy date" until the electronic system is modified.  This line reports end of period direct holdings for this reporting person, and 08/08/1988 is not a transaction date related to these securities.</footnote>
<footnote id="F3">There has been no transaction in the indirect holdings for this reporting person.</footnote>
</footnotes>
<ownerSignature><signatureName>Clark H. Masters</signatureName>
<signatureDate>2003-08-06</signatureDate>
</ownerSignature>
</ownershipDocument>

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