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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,
 Q+ee0BBFDZhiO43COaFOiscSxIGOX7dFrqoqI6Am3qn/P7SVXL0znD51zM0nQ9Wi
 qwbt6KfMr1W8F5+iybFUfQ==

<SEC-DOCUMENT>0000097745-04-000040.txt : 20040311
<SEC-HEADER>0000097745-04-000040.hdr.sgml : 20040311
<ACCEPTANCE-DATETIME>20040311114426
ACCESSION NUMBER:		0000097745-04-000040
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040310
FILED AS OF DATE:		20040311

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:		04662134

	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>the23.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-03-10</periodOfReport>

    <notSubjectToSection16>1</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>2004-03-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>250000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>12.99</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5435544.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>By: John A. Piccione, Assistant Secretary</signatureName>
        <signatureDate>2004-03-11</signatureDate>
    </ownerSignature>
</ownershipDocument>

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