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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,
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 oFBVodq4LzuFe7JmFa+7RA==

<SEC-DOCUMENT>0001062822-04-000001.txt : 20040105
<SEC-HEADER>0001062822-04-000001.hdr.sgml : 20040105
<ACCEPTANCE-DATETIME>20040105174629
ACCESSION NUMBER:		0001062822-04-000001
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031231
FILED AS OF DATE:		20040105

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			GREGORY JULIA P
		CENTRAL INDEX KEY:			0001226675

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-30111
		FILM NUMBER:		04506581

	MAIL ADDRESS:	
		STREET 1:		8800 TECHNOLOGY FOREST PLACE
		CITY:			THE WOODLANDS
		STATE:			TX
		ZIP:			77381

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			LEXICON GENETICS INC/TX
		CENTRAL INDEX KEY:			0001062822
		STANDARD INDUSTRIAL CLASSIFICATION:	IN VITRO & IN VIVO DIAGNOSTIC SUBSTANCES [2835]
		IRS NUMBER:				760474169
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		8800 TECHNOLOGY FOREST PLACE
		CITY:			THE WOODLANDS
		STATE:			TX
		ZIP:			77381
		BUSINESS PHONE:		2818633000

	MAIL ADDRESS:	
		STREET 1:		8800 TECHNOLOGY FOREST PLACE
		CITY:			THE WOODLANDS
		STATE:			TX
		ZIP:			77381
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>gre189.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
	<periodOfReport>2003-12-31</periodOfReport>
	<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0001062822</issuerCik>
        <issuerName>LEXICON GENETICS INC/TX</issuerName>
        <issuerTradingSymbol>LEXG</issuerTradingSymbol>
	</issuer>
	<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001226675</rptOwnerCik>
            <rptOwnerName>GREGORY JULIA P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>8800 TECHNOLOGY FOREST PLACE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>THE WOODLANDS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>773811160</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
			<isDirector>0</isDirector>
			<isOfficer>1</isOfficer>
			<isTenPercentOwner>0</isTenPercentOwner>
			<isOther>0</isOther>
			<officerTitle>EVP, Corp Dev and CFO</officerTitle>
		</reportingOwnerRelationship>
	</reportingOwner>
	<nonDerivativeTable>
		<nonDerivativeTransaction>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<transactionDate>
				<value>2003-12-31</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>G</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
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			<transactionAmounts>
				<transactionShares>
					<value>1000</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>0</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>57400.00</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value/>
				</natureOfOwnership>
			</ownershipNature>
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		<nonDerivativeTransaction>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<transactionDate>
				<value>2004-01-02</value>
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			<deemedExecutionDate>
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			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>M</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>20000</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>2.50</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>A</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>77400.00</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value/>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
		<nonDerivativeTransaction>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<transactionDate>
				<value>2004-01-02</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>S</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>3000</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>6.04</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>74400.00</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value/>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
		<nonDerivativeTransaction>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<transactionDate>
				<value>2004-01-02</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>S</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>1000</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>6.03</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>73400.00</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value/>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
		<nonDerivativeTransaction>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<transactionDate>
				<value>2004-01-02</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>S</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>1000</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>6.02</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>72400.00</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value/>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
		<nonDerivativeTransaction>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<transactionDate>
				<value>2004-01-02</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>S</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>1000</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>6.01</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>71400.00</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value/>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
		<nonDerivativeTransaction>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<transactionDate>
				<value>2004-01-02</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>S</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>800</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>6.00</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>70600.00</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value/>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
		<nonDerivativeTransaction>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<transactionDate>
				<value>2004-01-02</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>S</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>200</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>5.94</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>70400.00</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value/>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
		<nonDerivativeTransaction>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<transactionDate>
				<value>2004-01-02</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>S</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>1000</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>5.98</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>69400.00</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value/>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
		<nonDerivativeHolding>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>6647.00</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>I</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value>By Family Trusts for Minor Children</value>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeHolding>
	</nonDerivativeTable>
	<derivativeTable>
		<derivativeTransaction>
			<securityTitle>
				<value>Employee Stock Option (right to buy)</value>
			</securityTitle>
			<conversionOrExercisePrice>
				<value>2.50</value>
			</conversionOrExercisePrice>
			<transactionDate>
				<value>2004-01-02</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>M</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>20000</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>0</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<exerciseDate>
				<footnoteId id="F1"/>
			</exerciseDate>
			<expirationDate>
				<value>2010-02-08</value>
			</expirationDate>
			<underlyingSecurity>
				<underlyingSecurityTitle>
					<value>Common Stock</value>
				</underlyingSecurityTitle>
				<underlyingSecurityShares>
					<value>20000.00</value>
				</underlyingSecurityShares>
			</underlyingSecurity>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>465000.00</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value/>
				</natureOfOwnership>
			</ownershipNature>
		</derivativeTransaction>
	</derivativeTable>
	<footnotes>
		<footnote id="F1">Option vests with respect to 1/48th of the shares subject to the option for each month of service following the date of grant (2/8/2000).</footnote>
	</footnotes>
	<remarks>
	</remarks>
	<ownerSignature>
		<signatureName>/s/ Gregory, Julia P.</signatureName>
		<signatureDate>2004-01-05</signatureDate>
	</ownerSignature>
</ownershipDocument>

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