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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0001209191-10-059399.txt : 20101209
<SEC-HEADER>0001209191-10-059399.hdr.sgml : 20101209
<ACCEPTANCE-DATETIME>20101209164659
ACCESSION NUMBER:		0001209191-10-059399
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20101208
FILED AS OF DATE:		20101209
DATE AS OF CHANGE:		20101209

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			HENDRIX LEON J JR
		CENTRAL INDEX KEY:			0001198934

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09965
		FILM NUMBER:		101242778

	MAIL ADDRESS:	
		STREET 1:		340 SURFSONG RD
		CITY:			KIAWAH ISLAND
		STATE:			SC
		ZIP:			29455

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			KEITHLEY INSTRUMENTS INC
		CENTRAL INDEX KEY:			0000054991
		STANDARD INDUSTRIAL CLASSIFICATION:	INSTRUMENTS FOR MEAS & TESTING OF ELECTRICITY & ELEC SIGNALS [3825]
		IRS NUMBER:				340794417
		STATE OF INCORPORATION:			OH
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		28775 AURORA RD
		CITY:			SOLON
		STATE:			OH
		ZIP:			44139
		BUSINESS PHONE:		2162480400
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
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    <periodOfReport>2010-12-08</periodOfReport>

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        <issuerName>KEITHLEY INSTRUMENTS INC</issuerName>
        <issuerTradingSymbol>KEI</issuerTradingSymbol>
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            <rptOwnerStreet2>28775 AURORA ROAD</rptOwnerStreet2>
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            <rptOwnerState>OH</rptOwnerState>
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            <rptOwnerStateDescription></rptOwnerStateDescription>
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            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
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    <nonDerivativeTable>
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                <value>Common Shares</value>
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            <transactionAmounts>
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            <transactionDate>
                <value>2010-12-08</value>
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            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
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                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness>
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            <transactionAmounts>
                <transactionShares>
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                </transactionShares>
                <transactionPricePerShare>
                    <value>10.90</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
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            <exerciseDate>
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            <expirationDate>
                <value>2013-02-15</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
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                <underlyingSecurityShares>
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                </underlyingSecurityShares>
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                <sharesOwnedFollowingTransaction>
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        <derivativeTransaction>
            <securityTitle>
                <value>Common Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>23.13</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-12-08</value>
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            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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                <transactionPricePerShare>
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            <exerciseDate>
                <value>2004-08-15</value>
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            <expirationDate>
                <value>2014-02-14</value>
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                <value>2010-12-08</value>
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                <transactionPricePerShare>
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                <transactionAcquiredDisposedCode>
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            <exerciseDate>
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            <expirationDate>
                <value>2015-02-12</value>
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                    <value>D</value>
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        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F7"/>
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            <transactionDate>
                <value>2010-12-08</value>
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                <transactionShares>
                    <value>55064.07</value>
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                    <value>21.60</value>
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                    <value>D</value>
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    <footnotes>
        <footnote id="F1">Disposed of pursuant to an Agreement and Plan of Merger, dated as of September 29, 2010 (&quot;Merger Agreement&quot;) by and among Danaher Corporation, Aegean Acquisition Corp. and the Issuer in exchange for the merger consideration of $21.60 in cash per share.</footnote>
        <footnote id="F2">Bill Hendrix 2010 Grantor Retained Annuity Trust dated September 24, 2010</footnote>
        <footnote id="F3">The options were cancelled pursuant to the Merger Agreement.</footnote>
        <footnote id="F4">The options were cancelled pursuant to the Merger Agreement in exchange for the merger consideration of $21.60 in cash per share, less the exercise price per share of $19.23.</footnote>
        <footnote id="F5">The options were cancelled pursuant to the Merger Agreement in exchange for the merger consideration of $21.60 in cash per share, less the exercise price per share of $10.70.</footnote>
        <footnote id="F6">The options were cancelled pursuant to the Merger Agreement in exchange for the merger consideration of $21.60 in cash per share, less the exercise price per share of $16.67.</footnote>
        <footnote id="F7">Phantom shares were acquired on various dates (beginning 09/19/1995)with prices ranging from $2.469 to $64.00.</footnote>
        <footnote id="F8">The phantom stock units were accrued under the Keithley Instruments, Inc. Deferred Stock Plan and were to be settled in common stock or cash upon the retirement from the Board of the reporting person. The plan was terminated and liquidated at closing of the merger and, under the Merger Agreement, the Phantom Stock Units were cancelled in exchange for the merger consideration of $21.60 in cash per share.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Mark J. Plush, Attorney-in Fact</signatureName>
        <signatureDate>2010-12-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----