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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,
 UwCYc25zEV7yTYOyfsZg45ILz64S7JTBaESbT8BhTgim4rPJFyyquOFifDpmXnrQ
 PkHzen1YYFu+vkcTecB1cA==

<SEC-DOCUMENT>0001179110-03-008425.txt : 20031003
<SEC-HEADER>0001179110-03-008425.hdr.sgml : 20031003
<ACCEPTANCE-DATETIME>20031003144956
ACCESSION NUMBER:		0001179110-03-008425
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031003
FILED AS OF DATE:		20031003

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ARNOLD LYLE J
		CENTRAL INDEX KEY:			0001265721

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31279
		FILM NUMBER:		03927597

	MAIL ADDRESS:	
		STREET 1:		C/O GEN PROBE INC
		STREET 2:		10210 GENETIC CENTER DR
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			GEN PROBE INC
		CENTRAL INDEX KEY:			0000820237
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMMERCIAL PHYSICAL & BIOLOGICAL RESEARCH [8731]
		IRS NUMBER:				330044608
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		10210 GENETIC CENTER DR.
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121
		BUSINESS PHONE:		8584108000

	MAIL ADDRESS:	
		STREET 1:		10210 GENETIC CENTER DR
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
<periodOfReport>2003-10-03</periodOfReport>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000820237</issuerCik>
        <issuerName>GEN PROBE INC</issuerName>
        <issuerTradingSymbol>GPRO</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001265721</rptOwnerCik>
            <rptOwnerName>ARNOLD LYLE J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>GEN-PROBE INCORPORATED</rptOwnerStreet1>
            <rptOwnerStreet2>10210 GENETIC CENTER DRIVE</rptOwnerStreet2>
            <rptOwnerCity>SAN DIEGO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92121</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>1</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle>VP, Research</officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeTable></nonDerivativeTable>
<derivativeTable><derivativeTransaction><securityTitle><value>Employee Stock Option (Right to Buy)</value>
</securityTitle>
<conversionOrExercisePrice><value>27.08</value>
</conversionOrExercisePrice>
<transactionDate><value>2003-10-03</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>A</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>10000</value>
</transactionShares>
<transactionPricePerShare><value>0</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<exerciseDate><footnoteId id="F1"></footnoteId>
</exerciseDate>
<expirationDate><value>2013-10-01</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>10000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>10000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeTransaction>
</derivativeTable>
<footnotes><footnote id="F1">Option vests as follows: 25% vest on 10/1/04; 1/48th vesting monthly following three years.</footnote>
</footnotes>
<ownerSignature><signatureName>/s/ R. William Bowen, Attorney-in-Fact</signatureName>
<signatureDate>2003-10-03</signatureDate>
</ownerSignature>
</ownershipDocument>

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