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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 VPLm9Dzzt6V8juLUg5FVaOWiRsCJp6xbuwDkQMQRLX65FglWF4ktSg9btH34abMW
 QiTs1y3cJx+RhfWSTgmjrQ==

<SEC-DOCUMENT>0001179110-03-011164.txt : 20031121
<SEC-HEADER>0001179110-03-011164.hdr.sgml : 20031121
<ACCEPTANCE-DATETIME>20031121155642
ACCESSION NUMBER:		0001179110-03-011164
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031121
FILED AS OF DATE:		20031121

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MCCARTHY KEVIN
		CENTRAL INDEX KEY:			0001234405

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-05255
		FILM NUMBER:		031018252

	BUSINESS ADDRESS:	
		STREET 1:		PO BOX 54980
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95056

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			COHERENT INC
		CENTRAL INDEX KEY:			0000021510
		STANDARD INDUSTRIAL CLASSIFICATION:	LABORATORY ANALYTICAL INSTRUMENTS [3826]
		IRS NUMBER:				941622541
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		5100 PATRICK HENRY DR
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95054
		BUSINESS PHONE:		4087644000

	MAIL ADDRESS:	
		STREET 1:		5100 PATRICK HENRY DRIVE
		STREET 2:		MAIL STOP P38
		CITY:			SANTA CLARA
		STATE:			CA
		ZIP:			95054

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	COHERENT RADIATION
		DATE OF NAME CHANGE:	19770604
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
<periodOfReport>2003-11-21</periodOfReport>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000021510</issuerCik>
        <issuerName>COHERENT INC</issuerName>
        <issuerTradingSymbol>cohr</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001234405</rptOwnerCik>
            <rptOwnerName>MCCARTHY KEVIN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>P. O. BOX 54980</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SANTA CLARA</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95056-0980</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>1</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle>Exec VP &amp; CIO</officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Common Stock</value>
</securityTitle>
<transactionDate><value>2003-11-21</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>I</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>286</value>
</transactionShares>
<transactionPricePerShare><value>19.55</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>1805</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</nonDerivativeTransaction>
</nonDerivativeTable>
<derivativeTable></derivativeTable>
<footnotes></footnotes>
<ownerSignature><signatureName>Scott H. Miller, by power of atty</signatureName>
<signatureDate>2003-11-21</signatureDate>
</ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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