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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001140361-10-030622.txt : 20100728
<SEC-HEADER>0001140361-10-030622.hdr.sgml : 20100728
<ACCEPTANCE-DATETIME>20100728160519
ACCESSION NUMBER:		0001140361-10-030622
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100727
FILED AS OF DATE:		20100728
DATE AS OF CHANGE:		20100728

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			GUTSHALL THOMAS L
		CENTRAL INDEX KEY:			0001187325

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-30755
		FILM NUMBER:		10974434

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CEPHEID
		CENTRAL INDEX KEY:			0001037760
		STANDARD INDUSTRIAL CLASSIFICATION:	LABORATORY ANALYTICAL INSTRUMENTS [3826]
		IRS NUMBER:				770441625
		STATE OF INCORPORATION:			CA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		904 CARIBBEAN DRIVE
		CITY:			SUNNYVALE
		STATE:			CA
		ZIP:			94089
		BUSINESS PHONE:		4085414191

	MAIL ADDRESS:	
		STREET 1:		904 CARIBBEAN DRIVE
		CITY:			SUNNYVALE
		STATE:			CA
		ZIP:			94089
</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>2010-07-27</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001037760</issuerCik>
        <issuerName>CEPHEID</issuerName>
        <issuerTradingSymbol>CPHD</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001187325</rptOwnerCik>
            <rptOwnerName>GUTSHALL THOMAS L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CEPHEID</rptOwnerStreet1>
            <rptOwnerStreet2>904 CARIBBEAN DRIVE</rptOwnerStreet2>
            <rptOwnerCity>SUNNYVALE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94089</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>2010-07-27</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>16.87</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>881075</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>114025</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The transaction reported on this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on February 27, 2009.</footnote>
        <footnote id="F2">All shares are held by the Gutshall Family Trust DTD 3-7-90, of which the Reporting Person and his spouse are co-trustees.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Thomas L. Gutshall by Joseph H. Smith, Attorney-in-Fact</signatureName>
        <signatureDate>2010-07-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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