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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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 y7Snft63peRmh38H8vlHew==

<SEC-DOCUMENT>0001177454-04-000048.txt : 20040527
<SEC-HEADER>0001177454-04-000048.hdr.sgml : 20040527
<ACCEPTANCE-DATETIME>20040527162555
ACCESSION NUMBER:		0001177454-04-000048
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040525
FILED AS OF DATE:		20040527

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MARU HANSRAJ C
		CENTRAL INDEX KEY:			0001177403

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-14204
		FILM NUMBER:		04835420

	MAIL ADDRESS:	
		STREET 1:		FUELCELL ENERGY INC
		STREET 2:		3 GREAT PASTURE RD
		CITY:			DANBURY
		STATE:			CT
		ZIP:			06813-1305

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FUELCELL ENERGY INC
		CENTRAL INDEX KEY:			0000886128
		STANDARD INDUSTRIAL CLASSIFICATION:	MISCELLANEOUS ELECTRICAL MACHINERY, EQUIPMENT & SUPPLIES [3690]
		IRS NUMBER:				060853042
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1031

	BUSINESS ADDRESS:	
		STREET 1:		3 GREAT PASTURE RD
		CITY:			DANBURY
		STATE:			CT
		ZIP:			06813
		BUSINESS PHONE:		2038256000

	MAIL ADDRESS:	
		STREET 1:		3 GREAT PASTURE ROAD
		CITY:			DANBURY
		STATE:			CT
		ZIP:			06813

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ENERGY RESEARCH CORP /NY/
		DATE OF NAME CHANGE:	19930328
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-05-25</periodOfReport>

    <issuer>
        <issuerCik>0000886128</issuerCik>
        <issuerName>FUELCELL ENERGY INC</issuerName>
        <issuerTradingSymbol>FCEL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001177403</rptOwnerCik>
            <rptOwnerName>MARU HANSRAJ C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O FUELCELL ENERGY, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>3 GREAT PASTURE ROAD</rptOwnerStreet2>
            <rptOwnerCity>DANBURY</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06813</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Exec. VP &amp; Chief Tech. Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-04-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>94</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>13.77</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>46353</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-05-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>15000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>15.33</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>31353</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Voluntary reporting of acquisition of shares pursuant to the Company's Section 423 Stock Purchase Plan</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Jacqueline Perez-Ares, Attorney-in-fact</signatureName>
        <signatureDate>2004-05-26</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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