-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
 QJGwgcJDF4f0wykk2TUTMzZEZBwy8dlWbrNpoFfiUn7NIDvzzv2nYu4m9hu4TTbN
 rz4d2ApyU/f8eSDALZbzIw==

<SEC-DOCUMENT>0001179110-09-008704.txt : 20090528
<SEC-HEADER>0001179110-09-008704.hdr.sgml : 20090528
<ACCEPTANCE-DATETIME>20090528183323
ACCESSION NUMBER:		0001179110-09-008704
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090528
FILED AS OF DATE:		20090528
DATE AS OF CHANGE:		20090528

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Gottlieb Scott
		CENTRAL INDEX KEY:			0001411359

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33523
		FILM NUMBER:		09858570

	MAIL ADDRESS:	
		STREET 1:		MOLECULAR INSIGHT PHARMACEUTICALS
		STREET 2:		160 SECOND STREET
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CombiMatrix Corp
		CENTRAL INDEX KEY:			0001383183
		STANDARD INDUSTRIAL CLASSIFICATION:	LABORATORY ANALYTICAL INSTRUMENTS [3826]
		IRS NUMBER:				470899439
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		6500 HARBOUR HEIGHTS PKWY #301
		CITY:			MUKILTEO
		STATE:			WA
		ZIP:			98275
		BUSINESS PHONE:		425-493-2300

	MAIL ADDRESS:	
		STREET 1:		6500 HARBOUR HEIGHTS PKWY #301
		CITY:			MUKILTEO
		STATE:			WA
		ZIP:			98275
</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>2009-05-28</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001383183</issuerCik>
        <issuerName>CombiMatrix Corp</issuerName>
        <issuerTradingSymbol>CBMX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001411359</rptOwnerCik>
            <rptOwnerName>Gottlieb Scott</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O COMBIMATRIX CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>6500 HARBOUR HEIGHTS PARKWAY, STE. 303</rptOwnerStreet2>
            <rptOwnerCity>MUKILTEO</rptOwnerCity>
            <rptOwnerState>WA</rptOwnerState>
            <rptOwnerZipCode>98275</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>2009-05-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.4999</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes></footnotes>

    <ownerSignature>
        <signatureName>Scott Burell, as attorney-in-fact for Scott Gottlieb</signatureName>
        <signatureDate>2009-05-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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