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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0001209191-10-059390.txt : 20101209
<SEC-HEADER>0001209191-10-059390.hdr.sgml : 20101209
<ACCEPTANCE-DATETIME>20101209163602
ACCESSION NUMBER:		0001209191-10-059390
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20101208
FILED AS OF DATE:		20101209
DATE AS OF CHANGE:		20101209

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:			DANAHER CORP /DE/
		CENTRAL INDEX KEY:			0000313616
		STANDARD INDUSTRIAL CLASSIFICATION:	INDUSTRIAL INSTRUMENTS FOR MEASUREMENT, DISPLAY, AND CONTROL [3823]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09965
		FILM NUMBER:		101242696

	BUSINESS ADDRESS:	
		STREET 1:		2099 PENNSYLVANIA AVE N.W., 12TH FLOOR
		CITY:			WASHINGTON
		STATE:			DC
		ZIP:			20006
		BUSINESS PHONE:		2028280850

	MAIL ADDRESS:	
		STREET 1:		2099 PENNSYLVANIA AVE. N.W., 12TH FLOOR
		CITY:			WASHINGTON
		STATE:			DC
		ZIP:			20006

	FORMER NAME:	
		FORMER CONFORMED NAME:	DMG INC
		DATE OF NAME CHANGE:	19850221

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Aegean Acquisition Corp.
		CENTRAL INDEX KEY:			0001502907
		STATE OF INCORPORATION:			OH
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09965
		FILM NUMBER:		101242695

	BUSINESS ADDRESS:	
		STREET 1:		2099 PENNSYLVANIA AVENUE
		STREET 2:		12TH FLOOR
		CITY:			WASHINGTON
		STATE:			DC
		ZIP:			20006
		BUSINESS PHONE:		2028280850

	MAIL ADDRESS:	
		STREET 1:		2099 PENNSYLVANIA AVENUE
		STREET 2:		12TH FLOOR
		CITY:			WASHINGTON
		STATE:			DC
		ZIP:			20006
</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>2010-12-08</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000313616</rptOwnerCik>
            <rptOwnerName>DANAHER CORP /DE/</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2099 PENNSYLVANIA AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>12TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>WASHINGTON</rptOwnerCity>
            <rptOwnerState>DC</rptOwnerState>
            <rptOwnerZipCode>20006</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001502907</rptOwnerCik>
            <rptOwnerName>Aegean Acquisition Corp.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2099 PENNSYLVANIA AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>12TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>WASHINGTON</rptOwnerCity>
            <rptOwnerState>DC</rptOwnerState>
            <rptOwnerZipCode>20006</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Class B Common Shares</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-12-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Note</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This Form 4 is being filed as a result of the consummation of the merger of Aegean Acquisition Corp. (&quot;Merger Sub&quot; and together with Danaher Corporation, the &quot;Reporting Persons&quot;) with and into the Issuer on December 8, 2010.  In connection with the consummation of the merger, the separate corporate existence of Merger Sub thereupon ceased, and the Issuer became an indirectly wholly-owned subsidiary of Danaher.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ James F. O'Reilly, Associate General Counsel and Secretary, Danaher Corporation</signatureName>
        <signatureDate>2010-12-09</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ James F. O'Reilly, Vice President and Secretary, Aegean Acquisition Corp.</signatureName>
        <signatureDate>2010-12-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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