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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 P0b7VJEGmOpGkrNzD9A5rcwL+kyJ/ZRucJEuEq7puESI+Ptq2OrpMvZ/KedxJDqZ
 sKII7YFBdLNV4pZXFoPZFg==

<SEC-DOCUMENT>0001182084-03-000033.txt : 20031222
<SEC-HEADER>0001182084-03-000033.hdr.sgml : 20031222
<ACCEPTANCE-DATETIME>20031222175322
ACCESSION NUMBER:		0001182084-03-000033
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031222
FILED AS OF DATE:		20031222

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MCMANUS J T
		CENTRAL INDEX KEY:			0001182084

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-07810
		FILM NUMBER:		031068667

	MAIL ADDRESS:	
		STREET 1:		605 RICHARD ARRINGTON JR BLVD N
		CITY:			BIRMINGHAM
		STATE:			AL
		ZIP:			35203-2707

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ENERGEN CORP
		CENTRAL INDEX KEY:			0000277595
		STANDARD INDUSTRIAL CLASSIFICATION:	NATURAL GAS DISTRIBUTION [4924]
		IRS NUMBER:				630757759
		STATE OF INCORPORATION:			AL
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		605 RICHARD ARRINGTON JR BLVD N
		CITY:			BIRMINGHAM
		STATE:			AL
		ZIP:			35203-2707
		BUSINESS PHONE:		2053262997

	MAIL ADDRESS:	
		STREET 1:		605 RICHARD ARRINGTON JR BLVD N
		CITY:			BIRMINGHAM
		STATE:			AL
		ZIP:			35203

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALAGASCO INC
		DATE OF NAME CHANGE:	19851002
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
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<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-12-22</periodOfReport>
    <issuer>
        <issuerCik>0000277595</issuerCik>
        <issuerName>ENERGEN CORP</issuerName>
        <issuerTradingSymbol>EGN</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001182084</rptOwnerCik>
            <rptOwnerName>MCMANUS J T</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>605 RICHARD ARRINGTON JR. BLVD. NORTH</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BIRMINGHAM</rptOwnerCity>
            <rptOwnerState>AL</rptOwnerState>
            <rptOwnerZipCode>35203-2707</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>President and COO-ERC</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeHolding><securityTitle><value>Common Stock (ESP)</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5379</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>ESP</value><footnoteId id="F1"/></natureOfOwnership></ownershipNature></nonDerivativeHolding><nonDerivativeHolding><securityTitle><value>Common Stock (Restricted)</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>12107</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></own
ershipNature></nonDerivativeHolding><nonDerivativeTransaction><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-12-22</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>S</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>1000</value></transactionShares><transactionPricePerShare><value>40.40</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>8829</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>   (same as above)</value></securityTitle><transactionDate><valu
e>2003-12-22</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>S</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>844</value></transactionShares><transactionPricePerShare><value>40.35</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>7985</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>   (same as above)</value></securityTitle><transactionDate><value>2003-12-22</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>S</transactionCode><equit
ySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>1000</value></transactionShares><transactionPricePerShare><value>40.41</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>6985</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>   (same as above)</value></securityTitle><transactionDate><value>2003-12-22</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>4500</value></transactionShares><transac
tionPricePerShare><value>27.44</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>11485</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>   (same as above)</value></securityTitle><transactionDate><value>2003-12-22</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>F</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>3048</value></transactionShares><transactionPricePerShare><value>40.50</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDispos
edCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>8437</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeHolding><securityTitle><value>Common Stock (Deferred)</value><footnoteId id="F2"/></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>10040</value><footnoteId id="F3"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>Stock Option (Right to Buy) (ISO)</value></securityTitle><conversionOrExercisePrice><value>27.4375</value></conversionOrExercisePrice><transactionDate><
value>2003-12-22</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>4500</value></transactionShares><transactionPricePerShare><footnoteId id="F5"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F4"/></exerciseDate><expirationDate><value>2010-10-24</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>4500</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnershi
p></ownershipNature></derivativeTransaction><derivativeHolding><securityTitle><value>Stock Option (Right to Buy) (NQ)</value></securityTitle><conversionOrExercisePrice><value>22.63</value></conversionOrExercisePrice><exerciseDate><value>2004-10-24</value></exerciseDate><expirationDate><value>2011-10-23</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>2602</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>2602</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Stock Option (Right to Buy) (ISO)</value></securityTitle><conversionOrExercisePrice><value>22.63</value></conversionOrExercisePrice><exerciseDate><value>20
04-10-24</value></exerciseDate><expirationDate><value>2011-10-23</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>4418</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>4418</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Stock Option (Right to Buy) (ISO)</value></securityTitle><conversionOrExercisePrice><value>29.71</value></conversionOrExercisePrice><exerciseDate><value>2006-01-29</value></exerciseDate><expirationDate><value>2013-01-28</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>3365</value></under
lyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>3365</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Stock Option (Right to Buy) (NQ)</value></securityTitle><conversionOrExercisePrice><value>29.71</value></conversionOrExercisePrice><exerciseDate><value>2006-01-29</value></exerciseDate><expirationDate><value>2013-01-28</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>5285</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5285</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></di
rectOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">Energen Corporation Employee Savings Plan, number of Shares and Securities are estimates based on trustee's unit accounting.</footnote><footnote id="F2">Previously reported on Table II.</footnote><footnote id="F3">Energen Corporation Deferred Compensation Plan, number of securities is estimated based on recordkeepers' unit accounting. </footnote><footnote id="F4">The stock option becomes exercisable in two annual installments of 3,000 and 1,500 on October 25, 2002 and 2003, respectively.</footnote><footnote id="F5">Exercise or conversion of a derivative security.</footnote></footnotes><remarks/><ownerSignature><signatureName>J. D. Woodruff, Attorney in Fact</signatureName><signatureDate>2003-12-22</signatureDate></ownerSignature></ownershipDocument>

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