-----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,
 Be3CUhwXfuWiQ4A+0SQF+ZSg8MPJlBohWAyjjUpgk/5GP3T4oQ+ZoNeSOyVb7ZFw
 NPl4xX3ojV4wwh0LqV95mg==

<SEC-DOCUMENT>0001140361-04-001593.txt : 20040227
<SEC-HEADER>0001140361-04-001593.hdr.sgml : 20040227
<ACCEPTANCE-DATETIME>20040227120206
ACCESSION NUMBER:		0001140361-04-001593
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040225
FILED AS OF DATE:		20040227

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SYNTROLEUM CORP
		CENTRAL INDEX KEY:			0001029023
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		IRS NUMBER:				731565725
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1350 SOUTH BOULDER
		STREET 2:		SUITE 1100
		CITY:			TULSA
		STATE:			OK
		ZIP:			74119-3295
		BUSINESS PHONE:		9185927900

	MAIL ADDRESS:	
		STREET 1:		1350 SOUTH BOULDER
		STREET 2:		SUITE 1100
		CITY:			TULSA
		STATE:			OK
		ZIP:			74119-3295

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SLH CORP
		DATE OF NAME CHANGE:	19961213

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			RUSSELL BRANCH J
		CENTRAL INDEX KEY:			0001251480

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-21911
		FILM NUMBER:		04633479

	BUSINESS ADDRESS:	
		STREET 1:		C/O SYNTROLEUM CORP
		STREET 2:		1350 S. BOULDER #1100
		CITY:			TULSA
		STATE:			OK
		ZIP:			74119
		BUSINESS PHONE:		9185927900

	MAIL ADDRESS:	
		STREET 1:		C/O SYNTROLEUM CORP
		STREET 2:		1350 S. BOULDER #1100
		CITY:			TULSA
		STATE:			OK
		ZIP:			74119
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-02-25</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001029023</issuerCik>
        <issuerName>SYNTROLEUM CORP</issuerName>
        <issuerTradingSymbol>SYNM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001251480</rptOwnerCik>
            <rptOwnerName>RUSSELL BRANCH J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>4322 S. 49TH WEST AVE.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>TULSA</rptOwnerCity>
            <rptOwnerState>OK</rptOwnerState>
            <rptOwnerZipCode>74107</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice President</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-02-25</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2004-02-25</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>16667</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.6200</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>24817</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-02-25</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2004-02-25</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>16667</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.1267</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8150</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Incentive Stock Option Right to Buy</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1.6200</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-02-25</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2004-02-25</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>16667</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>1.6200</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2003-09-10</value>
            </exerciseDate>
            <expirationDate>
                <value>2012-09-10</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>16667</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>109039</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Branch Russell</signatureName>
        <signatureDate>2004-02-27</signatureDate>
    </ownerSignature>
</ownershipDocument>

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