<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
    <periodOfReport>2003-11-13</periodOfReport>
    <notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000731802</issuerCik>
        <issuerName>ATMOS ENERGY CORP</issuerName>
        <issuerTradingSymbol>ATO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001181021</rptOwnerCik>
            <rptOwnerName>GREGORY LOUIS P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5430 LBJ FREEWAY</rptOwnerStreet1>
            <rptOwnerStreet2>1800 III LINCOLN CENTRE</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75240</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Sr VP and General Counsel</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>
  <nonDerivativeTable>
   <nonDerivativeTransaction>
      <securityTitle>
          <value>Common Stock</value>
      </securityTitle>
      <transactionDate>
          <value>2003-11-11</value>
      </transactionDate>
      <transactionCoding>
          <transactionFormType>4</transactionFormType>
          <transactionCode>A</transactionCode>
          <equitySwapInvolved>0</equitySwapInvolved>
              <footnoteId id="F1" />
      </transactionCoding>
      <transactionTimeliness>
      <value />
      </transactionTimeliness>
      <transactionAmounts>
          <transactionShares>
              <value>909.00</value>
          </transactionShares>
          <transactionPricePerShare>
              <value>24.44</value>
          </transactionPricePerShare>
          <transactionAcquiredDisposedCode>
              <value>A</value>
          </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <postTransactionAmounts>
          <sharesOwnedFollowingTransaction>
              <value>8631.00</value>
          </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
          <directOrIndirectOwnership>
              <value>D</value>
          </directOrIndirectOwnership>
      </ownershipNature>
   </nonDerivativeTransaction>
   <nonDerivativeTransaction>
      <securityTitle>
          <value>Common Stock</value>
      </securityTitle>
      <transactionDate>
          <value>2003-11-11</value>
      </transactionDate>
      <transactionCoding>
          <transactionFormType>4</transactionFormType>
          <transactionCode>F</transactionCode>
          <equitySwapInvolved>0</equitySwapInvolved>
              <footnoteId id="F2" />
      </transactionCoding>
      <transactionTimeliness>
      <value />
      </transactionTimeliness>
      <transactionAmounts>
          <transactionShares>
              <value>331.00</value>
          </transactionShares>
          <transactionPricePerShare>
              <value>24.44</value>
          </transactionPricePerShare>
          <transactionAcquiredDisposedCode>
              <value>D</value>
          </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <postTransactionAmounts>
          <sharesOwnedFollowingTransaction>
              <value>8300.00</value>
          </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
          <directOrIndirectOwnership>
              <value>D</value>
          </directOrIndirectOwnership>
      </ownershipNature>
   </nonDerivativeTransaction>
   <nonDerivativeTransaction>
      <securityTitle>
          <value>Common Stock</value>
      </securityTitle>
      <transactionDate>
          <value>2003-11-11</value>
      </transactionDate>
      <transactionCoding>
          <transactionFormType>4</transactionFormType>
          <transactionCode>A</transactionCode>
          <equitySwapInvolved>0</equitySwapInvolved>
              <footnoteId id="F3" />
      </transactionCoding>
      <transactionTimeliness>
      <value />
      </transactionTimeliness>
      <transactionAmounts>
          <transactionShares>
              <value>2480.00</value>
          </transactionShares>
          <transactionPricePerShare>
              <value>24.44</value>
          </transactionPricePerShare>
          <transactionAcquiredDisposedCode>
              <value>A</value>
          </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <postTransactionAmounts>
          <sharesOwnedFollowingTransaction>
              <value>10780.00</value>
          </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
          <directOrIndirectOwnership>
              <value>D</value>
          </directOrIndirectOwnership>
      </ownershipNature>
   </nonDerivativeTransaction>
    <nonDerivativeHolding>
      <securityTitle>
          <value>Common Stock</value>
      </securityTitle>
      <postTransactionAmounts>
          <sharesOwnedFollowingTransaction>
              <value>1777.81</value>
              <footnoteId id="F4" />
          </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
          <directOrIndirectOwnership>
              <value>I</value>
          </directOrIndirectOwnership>
          <natureOfOwnership>
              <value>ESOP Trust</value>
          </natureOfOwnership>
      </ownershipNature>
   </nonDerivativeHolding>
  </nonDerivativeTable>
  <derivativeTable>
  </derivativeTable>
<footnotes>
   <footnote id="F1">Award of common stock issued in lieu of cash, which was granted under the Atmos Energy Corporation Annual Incentive Plan for Mana
gement, in a transaction exempt under Rule 16b-3. </footnote>
   <footnote id="F2">Shares withheld pursuant to a tax withholding obligation under the Atmos Energy Corporation Annual Incentive Plan for Management,
 in a transaction exempt under Rule 16b-3.</footnote>
   <footnote id="F3">Award of restricted stock in lieu of cash granted under the Atmos Energy Corporation Annual Incentive Plan for Management, in a t
ransaction exempt under Rule 16b-3.</footnote>
   <footnote id="F4">To update end of period holdings as of 10/31/03 under the Atmos Energy Corporation Retirement Savings Plan and Trust (formerly kn
own as the Atmos Energy Corporation Employee Stock Ownership Plan and Trust.)</footnote>
</footnotes>
<remarks></remarks>    <ownerSignature>
       <signatureName>Dwala Kuhn by POA</signatureName>
       <signatureDate>2003-11-13</signatureDate>
    </ownerSignature>
</ownershipDocument>

