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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0001209191-09-024723.txt : 20090506
<SEC-HEADER>0001209191-09-024723.hdr.sgml : 20090506
<ACCEPTANCE-DATETIME>20090506152821
ACCESSION NUMBER:		0001209191-09-024723
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090504
FILED AS OF DATE:		20090506
DATE AS OF CHANGE:		20090506

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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SAPONAS THOMAS A
		CENTRAL INDEX KEY:			0001142625

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09965
		FILM NUMBER:		09801250

	MAIL ADDRESS:	
		STREET 1:		395 PAGE MILL RD
		STREET 2:		MS A3 18
		CITY:			PALO ALTO
		STATE:			CA
		ZIP:			94306
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-05-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000054991</issuerCik>
        <issuerName>KEITHLEY INSTRUMENTS INC</issuerName>
        <issuerTradingSymbol>KEI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001142625</rptOwnerCik>
            <rptOwnerName>SAPONAS THOMAS A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>28775 AURORA ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SOLON</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>44139</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2009-05-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>3000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>28673</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.089</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-05-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2832.54</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stk</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2832.54</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>18359.66</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Includes 5,098 shares for which restrictions lapsed on February 13, 2009, which were previously reported as restricted.</footnote>
        <footnote id="F2">The phantom stock units were accrued under the Keithley Instruments, Inc. Deferred Stock Plan and are to be settled in common stock or cash upon the retirement from the Board of the Reporting person; retirement date is not yet known</footnote>
        <footnote id="F3">Phantom shares were acquired on various dates (beginning 2/13/06) with prices ranging from $3.2412 to $15.59.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Mark J. Plush, Attorney-in Fact</signatureName>
        <signatureDate>2009-05-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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