-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Ng5OoA9o3j7dfcRTi9DngS2K/NZQpGJyoPCRdxprhUyX6nTeCD0wy33IvgCLEyBK
 942A9bztwqQYaJlP5VyYxQ==

<SEC-DOCUMENT>0001179110-10-001731.txt : 20100201
<SEC-HEADER>0001179110-10-001731.hdr.sgml : 20100201
<ACCEPTANCE-DATETIME>20100201171550
ACCESSION NUMBER:		0001179110-10-001731
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090311
FILED AS OF DATE:		20100201
DATE AS OF CHANGE:		20100201

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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ROGERSON GARRY W
		CENTRAL INDEX KEY:			0001232125

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33962
		FILM NUMBER:		10564191

	MAIL ADDRESS:	
		STREET 1:		3120 HANSEN WAY
		CITY:			PALO ALTO
		STATE:			CA
		ZIP:			943041030
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4 -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-03-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000021510</issuerCik>
        <issuerName>COHERENT INC</issuerName>
        <issuerTradingSymbol>COHR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001232125</rptOwnerCik>
            <rptOwnerName>ROGERSON GARRY W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>P. O. BOX 54980</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SANTA CLARA</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95056</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-03-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2012-03-11</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>55000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Non-Qualified Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>15.21</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-03-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>6000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>15.21</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2019-03-11</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>61000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Automatic grant under the 1998 Director Plan.  Grant of restricted stock units cliff vesting on the day prior to the annual stockholder's meeting held three calendar years from the date of grant. Each restricted stock unit represents a contingent right to receive one share of Coherent common stock.</footnote>
        <footnote id="F2">Automatic grant under the 1998 Director Plan.  These options become exercisable as to one half of the common shares on the day prior to each of the next two annual stockholder's meetings.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Bret DiMarco, Pursuant to Power of Attorney</signatureName>
        <signatureDate>2010-02-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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