-----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,
 BPRDUAlj4SbQakigSKzOvuMS94Xj7Vos4RqYHsP7Mz46rj4Oj6BALk0tIZk4o5vB
 EqkfJrXVU6ErkYA7swlyCw==

<SEC-DOCUMENT>0001140361-10-042432.txt : 20101027
<SEC-HEADER>0001140361-10-042432.hdr.sgml : 20101027
<ACCEPTANCE-DATETIME>20101027165020
ACCESSION NUMBER:		0001140361-10-042432
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20101004
FILED AS OF DATE:		20101027
DATE AS OF CHANGE:		20101027

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			McCorkle Sherman
		CENTRAL INDEX KEY:			0001479494

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22175
		FILM NUMBER:		101145350

	MAIL ADDRESS:	
		STREET 1:		C/O EMCORE CORPORATIO
		STREET 2:		10420 RESEARCH ROAD SE
		CITY:			ALBUQUERQUE
		STATE:			NM
		ZIP:			87123

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			EMCORE CORP
		CENTRAL INDEX KEY:			0000808326
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				222746503
		STATE OF INCORPORATION:			NJ
		FISCAL YEAR END:			0930

	BUSINESS ADDRESS:	
		STREET 1:		10420 RESEARCH ROAD, SE
		CITY:			ALBUQUERQUE
		STATE:			NM
		ZIP:			87123
		BUSINESS PHONE:		505-332-5000

	MAIL ADDRESS:	
		STREET 1:		10420 RESEARCH ROAD, SE
		CITY:			ALBUQUERQUE
		STATE:			NM
		ZIP:			87123
</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>2010-10-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000808326</issuerCik>
        <issuerName>EMCORE CORP</issuerName>
        <issuerTradingSymbol>EMKR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001479494</rptOwnerCik>
            <rptOwnerName>McCorkle Sherman</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O EMCORE CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>10420 RESEARCH ROAD SE</rptOwnerStreet2>
            <rptOwnerCity>ALBQUERQUE</rptOwnerCity>
            <rptOwnerState>NM</rptOwnerState>
            <rptOwnerZipCode>87123</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>COMMON STOCK</value>
            </securityTitle>
            <transactionDate>
                <value>2010-10-04</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>I</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.78</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>41000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>BY 401(K) PLAN</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Sherman McCorkle</signatureName>
        <signatureDate>2010-10-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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