-----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,
 J3q26gcca4dp1J6290sCfincEnq+0T8ez5XI8VF8cUuiTxizz0Mkz+btifRJZXla
 zoYWmsEgXSyDCZ8zg5L5oA==

<SEC-DOCUMENT>0001179110-04-023201.txt : 20041214
<SEC-HEADER>0001179110-04-023201.hdr.sgml : 20041214
<ACCEPTANCE-DATETIME>20041214182738
ACCESSION NUMBER:		0001179110-04-023201
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20041214
FILED AS OF DATE:		20041214
DATE AS OF CHANGE:		20041214

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CARRUBBA FRANK P
		CENTRAL INDEX KEY:			0001193280

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-05255
		FILM NUMBER:		041202835

	BUSINESS ADDRESS:	
		STREET 1:		48720 KATO ROAD
		CITY:			FREMONT
		STATE:			CA
		ZIP:			94538

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>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-12-14</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001193280</rptOwnerCik>
            <rptOwnerName>CARRUBBA FRANK P</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>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>Scott H. Miller, by power of atty</signatureName>
        <signatureDate>2004-12-14</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----