-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 JHGRfu6bzb86HMNFxL7pYChuJWdAtgTzXmK3IkSaCVEt9Kvrb0tmJ+rbVmn0EkX8
 28BImS7OeNWllDcLE9Fd+g==

<SEC-DOCUMENT>0001179110-04-001430.txt : 20040120
<SEC-HEADER>0001179110-04-001430.hdr.sgml : 20040119
<ACCEPTANCE-DATETIME>20040120191139
ACCESSION NUMBER:		0001179110-04-001430
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031001
FILED AS OF DATE:		20040120

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			GENAISSANCE PHARMACEUTICALS INC
		CENTRAL INDEX KEY:			0001110009
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMMERCIAL PHYSICAL & BIOLOGICAL RESEARCH [8731]
		IRS NUMBER:				061338846
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		FIVE SCIENCE PARK
		CITY:			NEW HAVEN
		STATE:			CT
		ZIP:			06511
		BUSINESS PHONE:		2037731450

	MAIL ADDRESS:	
		STREET 1:		FIVE SCIENCE PARK
		CITY:			NEW HAVEN
		STATE:			CT
		ZIP:			06511

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PENNER HARRY JR
		CENTRAL INDEX KEY:			0001131148

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-30981
		FILM NUMBER:		04533616

	BUSINESS ADDRESS:	
		STREET 1:		C/O GENAISSANCE PHARMACEUTICALS
		STREET 2:		5 SCIENCE PARK
		CITY:			NEW HAVEN
		STATE:			CT
		ZIP:			06511
		BUSINESS PHONE:		2037731450

	MAIL ADDRESS:	
		STREET 1:		C/O GENAISSANCE PHARMACEUTICALS
		STREET 2:		5 SCIENCE PARK
		CITY:			NEW HAVEN
		STATE:			CT
		ZIP:			06511
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
<periodOfReport>2003-10-01</periodOfReport>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0001110009</issuerCik>
        <issuerName>GENAISSANCE PHARMACEUTICALS INC</issuerName>
        <issuerTradingSymbol>GNSC</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001131148</rptOwnerCik>
            <rptOwnerName>PENNER HARRY JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O GENAISSANCE PHARMACEUTICALS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>FIVE SCIENCE PARK</rptOwnerStreet2>
            <rptOwnerCity>NEW HAVEN</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06511</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector>
<isOfficer>0</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle></officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeTable></nonDerivativeTable>
<derivativeTable><derivativeTransaction><securityTitle><value>Stock Option (Right to buy)</value>
</securityTitle>
<conversionOrExercisePrice><value>2.10</value>
</conversionOrExercisePrice>
<transactionDate><value>2003-10-01</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>A</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>5000</value>
</transactionShares>
<transactionPricePerShare><value>2.10</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<exerciseDate><value>2007-10-01</value>
<footnoteId id="F1"></footnoteId>
</exerciseDate>
<expirationDate><value>2013-10-01</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>5000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>5000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeTransaction>
</derivativeTable>
<footnotes><footnote id="F1">This option vests quarterly over 4 years.</footnote>
</footnotes>
<ownerSignature><signatureName>Kevin Rakin as Power of Attorney</signatureName>
<signatureDate>2004-01-20</signatureDate>
</ownerSignature>
</ownershipDocument>

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