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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 KbwM2nPAjXUtKYnvWMj1d91QTh3lkN5OkXmyciWbcpJ9ZWTW3wLhwY3s9X59l8vr
 26qJrazqG+rUG8ySQCW08A==

<SEC-DOCUMENT>0000097745-03-000203.txt : 20031218
<SEC-HEADER>0000097745-03-000203.hdr.sgml : 20031218
<ACCEPTANCE-DATETIME>20031218142704
ACCESSION NUMBER:		0000097745-03-000203
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031216
FILED AS OF DATE:		20031218

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			THORATEC CORP
		CENTRAL INDEX KEY:			0000350907
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTROMEDICAL & ELECTROTHERAPEUTIC APPARATUS [3845]
		IRS NUMBER:				942340464
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			0102

	BUSINESS ADDRESS:	
		STREET 1:		6035 STONERIDGE DR
		CITY:			PLEASANTON
		STATE:			CA
		ZIP:			94588
		BUSINESS PHONE:		9258478600

	MAIL ADDRESS:	
		STREET 1:		6035 STONERIDGE DR
		CITY:			PLEASANTON
		STATE:			CA
		ZIP:			94588

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	THORATEC CARDIOSYSTEMS INC
		DATE OF NAME CHANGE:	20010220

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	THORATEC LABORATORIES CORP
		DATE OF NAME CHANGE:	19920703

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			THERMO ELECTRON CORP
		CENTRAL INDEX KEY:			0000097745
		STANDARD INDUSTRIAL CLASSIFICATION:	MEASURING & CONTROLLING DEVICES, NEC [3829]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-49798
		FILM NUMBER:		031062036

	BUSINESS ADDRESS:	
		STREET 1:		81 WYMAN ST
		STREET 2:		PO BOX 9046
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
		BUSINESS PHONE:		7816221000

	MAIL ADDRESS:	
		STREET 1:		81 WYMAN ST
		STREET 2:		PO BOX 9046
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>the14.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
	<periodOfReport>2003-12-16</periodOfReport>
	<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000350907</issuerCik>
        <issuerName>THORATEC CORP</issuerName>
        <issuerTradingSymbol>THOR</issuerTradingSymbol>
	</issuer>
	<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000097745</rptOwnerCik>
            <rptOwnerName>THERMO ELECTRON CORP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>81 WYMAN STREET</rptOwnerStreet1>
            <rptOwnerStreet2>P.O. BOX 9046</rptOwnerStreet2>
            <rptOwnerCity>WALTHAM</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02454</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
			<isDirector>0</isDirector>
			<isOfficer>0</isOfficer>
			<isTenPercentOwner>1</isTenPercentOwner>
			<isOther>0</isOther>
		</reportingOwnerRelationship>
	</reportingOwner>
	<nonDerivativeTable>
		<nonDerivativeTransaction>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<transactionDate>
				<value>2003-12-16</value>
			</transactionDate>
			<deemedExecutionDate>
			</deemedExecutionDate>
			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>S</transactionCode>
				<equitySwapInvolved>0</equitySwapInvolved>
			</transactionCoding>
			<transactionAmounts>
				<transactionShares>
					<value>1000000</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>12.45</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>
				<sharesOwnedFollowingTransaction>
					<value>5685544.00</value>
				</sharesOwnedFollowingTransaction>
			</postTransactionAmounts>
			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>
					<value/>
				</natureOfOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>
	</nonDerivativeTable>
	<footnotes>
	</footnotes>
	<ownerSignature>
		<signatureName>By: Theo Melas-Kyriazi, VP and CFO</signatureName>
		<signatureDate>2003-12-18</signatureDate>
	</ownerSignature>
</ownershipDocument>

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