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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 TLDjs4+kAUR1S57upXA+rEUS2zPYQNz6lZ5CcNIZU4GGPtKqxEAyurlma3ftSj93
 Tjg2PlqjBWkkf3AzNhJFRQ==

<SEC-DOCUMENT>0001179110-09-016722.txt : 20091210
<SEC-HEADER>0001179110-09-016722.hdr.sgml : 20091210
<ACCEPTANCE-DATETIME>20091210165251
ACCESSION NUMBER:		0001179110-09-016722
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20091210
FILED AS OF DATE:		20091210
DATE AS OF CHANGE:		20091210

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Anderson Roger W
		CENTRAL INDEX KEY:			0001478219

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-21236
		FILM NUMBER:		091234213

	MAIL ADDRESS:	
		STREET 1:		7983 KESSINGTON COURT
		CITY:			MELBOURNE
		STATE:			FL
		ZIP:			32940

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			APPLIED SIGNAL TECHNOLOGY INC
		CENTRAL INDEX KEY:			0000741696
		STANDARD INDUSTRIAL CLASSIFICATION:	COMMUNICATIONS EQUIPMENT, NEC [3669]
		IRS NUMBER:				770015491
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			1031

	BUSINESS ADDRESS:	
		STREET 1:		400 WEST CALIFORNIA AVENUE
		CITY:			SUNNYVALE
		STATE:			CA
		ZIP:			94086
		BUSINESS PHONE:		4087491888

	MAIL ADDRESS:	
		STREET 1:		400 W CALIFORNIA
		CITY:			SUNNYVALE
		STATE:			CA
		ZIP:			94086
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 3 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0203</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2009-12-10</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000741696</issuerCik>
        <issuerName>APPLIED SIGNAL TECHNOLOGY INC</issuerName>
        <issuerTradingSymbol>APSG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001478219</rptOwnerCik>
            <rptOwnerName>Anderson Roger W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7983 KESSINGTON COURT</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MELBOURNE</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>32940</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP-Network Intelligence</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>Roger W Anderson</signatureName>
        <signatureDate>2009-12-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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