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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001239383-06-000004.txt : 20060103
<SEC-HEADER>0001239383-06-000004.hdr.sgml : 20060102
<ACCEPTANCE-DATETIME>20060103171236
ACCESSION NUMBER:		0001239383-06-000004
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20051231
FILED AS OF DATE:		20060103
DATE AS OF CHANGE:		20060103

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CASAL EILEEN
		CENTRAL INDEX KEY:			0001239383

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-06462
		FILM NUMBER:		06503358

	BUSINESS ADDRESS:	
		STREET 1:		TERADYNE INC
		STREET 2:		321 HARRISON AVENUE
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02118
		BUSINESS PHONE:		978 370 1223

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TERADYNE INC
		CENTRAL INDEX KEY:			0000097210
		STANDARD INDUSTRIAL CLASSIFICATION:	INSTRUMENTS FOR MEAS & TESTING OF ELECTRICITY & ELEC SIGNALS [3825]
		IRS NUMBER:				042272148
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		321 HARRISON AVE
		STREET 2:		MAIL STOP H93
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02118
		BUSINESS PHONE:		6174822700

	MAIL ADDRESS:	
		STREET 1:		321 HARRISON AVENUE
		STREET 2:		H93
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02118
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-12-31</periodOfReport>

    <issuer>
        <issuerCik>0000097210</issuerCik>
        <issuerName>TERADYNE INC</issuerName>
        <issuerTradingSymbol>TER</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001239383</rptOwnerCik>
            <rptOwnerName>CASAL EILEEN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TERADYNE, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>321 HARRISON AVENUE</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02118</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP, General Counsel &amp;Secretary</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2005-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1049</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.1193</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3463</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares acquired pursuant to Teradyne 1996 Employee Stock Purchase Plan under Section 423 of the Internal Revenue Code of 1986, as amended, in a transaction exempt under Rule 16b-3.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Eileen Casal, General Counsel</signatureName>
        <signatureDate>2006-01-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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