-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 N+JB9316xWwPwti3JkfKVTk4fp/BfHsqvCTYOMiCQQ13K9zba2YFaGAo4v8MvbhX
 +Cjr6FQJwxcbJ5zb3cr7ng==

<SEC-DOCUMENT>0001140361-10-039479.txt : 20101004
<SEC-HEADER>0001140361-10-039479.hdr.sgml : 20101004
<ACCEPTANCE-DATETIME>20101004123229
ACCESSION NUMBER:		0001140361-10-039479
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20101001
FILED AS OF DATE:		20101004
DATE AS OF CHANGE:		20101004

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			RICHEY VICTOR L JR
		CENTRAL INDEX KEY:			0001216231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10596
		FILM NUMBER:		101104679

	MAIL ADDRESS:	
		STREET 1:		C/O ESCO TECHNOLOGIES
		STREET 2:		9900 A CLAYTON ROAD
		CITY:			ST. LOUIS
		STATE:			MO
		ZIP:			63124

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ESCO TECHNOLOGIES INC
		CENTRAL INDEX KEY:			0000866706
		STANDARD INDUSTRIAL CLASSIFICATION:	COMMUNICATIONS EQUIPMENT, NEC [3669]
		IRS NUMBER:				431554045
		STATE OF INCORPORATION:			MO
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		9900 A CLAYTON RD
		CITY:			ST LOUIS
		STATE:			MO
		ZIP:			63124
		BUSINESS PHONE:		3142137200

	MAIL ADDRESS:	
		STREET 1:		9900 A CLAYTON RD
		CITY:			ST LOUIS
		STATE:			MO
		ZIP:			63124

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ESCO ELECTRONICS CORP
		DATE OF NAME CHANGE:	19920703
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-10-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000866706</issuerCik>
        <issuerName>ESCO TECHNOLOGIES INC</issuerName>
        <issuerTradingSymbol>ESE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001216231</rptOwnerCik>
            <rptOwnerName>RICHEY VICTOR L JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>9900 CLAYTON ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE A</rptOwnerStreet2>
            <rptOwnerCity>ST LOUIS</rptOwnerCity>
            <rptOwnerState>MO</rptOwnerState>
            <rptOwnerZipCode>63124</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman, CEO &amp; President</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-10-01</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5593</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.26</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>326220</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Includes 4,439 shares acquired in fiscal year ended 9-30-10 under Employee Stock Purchase Plan.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>V. L. Richey, Jr.</signatureName>
        <signatureDate>2010-10-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----