<?xml version="1.0"?>
<edgarSubmission>

    <schemaVersion>X0704</schemaVersion>

    <submissionType>D/A</submissionType>

    <testOrLive>LIVE</testOrLive>

    <primaryIssuer>
        <cik>0001505987</cik>
        <entityName>Aztec XI-B Oil &amp; Gas LP/Aztec Energy LLC</entityName>
        <issuerAddress>
            <street1>ONE RIVERWAY</street1>
            <street2>SUITE 1580</street2>
            <city>HOUSTON</city>
            <stateOrCountry>TX</stateOrCountry>
            <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
            <zipCode>77056</zipCode>
        </issuerAddress>
        <issuerPhoneNumber>(713) 840-6444</issuerPhoneNumber>
        <jurisdictionOfInc>NEVADA</jurisdictionOfInc>
        <issuerPreviousNameList>
            <value>None</value>
        </issuerPreviousNameList>
        <edgarPreviousNameList>
            <value>None</value>
        </edgarPreviousNameList>
        <entityType>Other</entityType>
        <entityTypeOtherDesc>Aztec XI Program (the Program) is the offering subject of this filing. If accepted, investors become partners of a partnership with Aztec Energy LLC Managing General Partner. Only one partnership is offered at a time until closed.</entityTypeOtherDesc>
        <yearOfInc>
            <withinFiveYears>true</withinFiveYears>
            <value>2010</value>
        </yearOfInc>
    </primaryIssuer>

    <relatedPersonsList>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Kenneth</firstName>
                <lastName>Lehrer</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>One Riverway</street1>
                <street2>Suite 1580</street2>
                <city>Houston</city>
                <stateOrCountry>TX</stateOrCountry>
                <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                <zipCode>77056</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Director of Aztec Oil &amp; Gas, Inc.</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Mark</firstName>
                <lastName>Vance</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>One Riverway</street1>
                <street2>Suite 1580</street2>
                <city>Houston</city>
                <stateOrCountry>TX</stateOrCountry>
                <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                <zipCode>77056</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Director of Aztec Oil &amp; Gas, Inc.</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Larry</firstName>
                <lastName>Hornbrook</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>One Riverway</street1>
                <street2>Suite 1580</street2>
                <city>Houston</city>
                <stateOrCountry>TX</stateOrCountry>
                <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                <zipCode>77056</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>CFO of Aztec Oil &amp; Gas, Inc.</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Dayton</firstName>
                <lastName>Wheeler</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>One Riverway</street1>
                <street2>Suite 1580</street2>
                <city>Houston</city>
                <stateOrCountry>TX</stateOrCountry>
                <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                <zipCode>77056</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Director of Aztec Oil &amp; Gas, Inc.</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Ariane</firstName>
                <lastName>Cox</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>One Riverway</street1>
                <street2>Suite 1580</street2>
                <city>Houston</city>
                <stateOrCountry>TX</stateOrCountry>
                <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                <zipCode>77056</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>Vice President, Secretary-Treasurer, and Administrative Coordinator of Aztec Oil &amp; Gas, Inc.</relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Waylan</firstName>
                <lastName>Johnson</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>One Riverway</street1>
                <street2>Suite 1580</street2>
                <city>Houston</city>
                <stateOrCountry>TX</stateOrCountry>
                <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                <zipCode>77056</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification>President, Aztec Oil &amp; Gas, Inc.</relationshipClarification>
        </relatedPersonInfo>
    </relatedPersonsList>

    <offeringData>
        <industryGroup>
            <industryGroupType>Oil and Gas</industryGroupType>
        </industryGroup>
        <issuerSize>
            <revenueRange>$5,000,001 - $25,000,000</revenueRange>
        </issuerSize>
        <federalExemptionsExclusions>
            <item>06</item>
        </federalExemptionsExclusions>
        <typeOfFiling>
            <newOrAmendment>
                <isAmendment>true</isAmendment>
                <previousAccessionNumber>0001505987-10-000001</previousAccessionNumber>
            </newOrAmendment>
            <dateOfFirstSale>
                <value>2010-11-29</value>
            </dateOfFirstSale>
        </typeOfFiling>
        <durationOfOffering>
            <moreThanOneYear>false</moreThanOneYear>
        </durationOfOffering>
        <typesOfSecuritiesOffered>
            <isOtherType>true</isOtherType>
            <descriptionOfOtherType>Limited Partnership Units</descriptionOfOtherType>
        </typesOfSecuritiesOffered>
        <businessCombinationTransaction>
            <isBusinessCombinationTransaction>false</isBusinessCombinationTransaction>
            <clarificationOfResponse></clarificationOfResponse>
        </businessCombinationTransaction>
        <minimumInvestmentAccepted>50000</minimumInvestmentAccepted>
        <salesCompensationList>
            <recipient>
                <recipientName>Frank Currie</recipientName>
                <recipientCRDNumber>1207937</recipientCRDNumber>
                <associatedBDName>IMS Securities, Inc.</associatedBDName>
                <associatedBDCRDNumber>35567</associatedBDCRDNumber>
                <recipientAddress>
                    <street1>10205 Westheimer</street1>
                    <street2>Suite 500</street2>
                    <city>Houston</city>
                    <stateOrCountry>TX</stateOrCountry>
                    <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                    <zipCode>77042</zipCode>
                </recipientAddress>
                <statesOfSolicitationList>
                    <state>TX</state>
                    <description>TEXAS</description>
                </statesOfSolicitationList>
                <foreignSolicitation>false</foreignSolicitation>
            </recipient>
            <recipient>
                <recipientName>Jeffrey R. Nesseth</recipientName>
                <recipientCRDNumber>1983482</recipientCRDNumber>
                <associatedBDName>QA3 Financial Corp.</associatedBDName>
                <associatedBDCRDNumber>14754</associatedBDCRDNumber>
                <recipientAddress>
                    <street1>7000 Central Parkway</street1>
                    <street2>Suite 1340</street2>
                    <city>Atlanta</city>
                    <stateOrCountry>GA</stateOrCountry>
                    <stateOrCountryDescription>GEORGIA</stateOrCountryDescription>
                    <zipCode>30328</zipCode>
                </recipientAddress>
                <statesOfSolicitationList>
                    <state>GA</state>
                    <description>GEORGIA</description>
                </statesOfSolicitationList>
                <foreignSolicitation>false</foreignSolicitation>
            </recipient>
            <recipient>
                <recipientName>Steve Barton</recipientName>
                <recipientCRDNumber>2788138</recipientCRDNumber>
                <associatedBDName>QA3 Financial</associatedBDName>
                <associatedBDCRDNumber>14754</associatedBDCRDNumber>
                <recipientAddress>
                    <street1>7000 Central Parkway</street1>
                    <street2>Suite 1340</street2>
                    <city>Atlanta</city>
                    <stateOrCountry>GA</stateOrCountry>
                    <stateOrCountryDescription>GEORGIA</stateOrCountryDescription>
                    <zipCode>30328</zipCode>
                </recipientAddress>
                <statesOfSolicitationList>
                    <state>GA</state>
                    <description>GEORGIA</description>
                </statesOfSolicitationList>
                <foreignSolicitation>false</foreignSolicitation>
            </recipient>
            <recipient>
                <recipientName>Don DeWaay</recipientName>
                <recipientCRDNumber>1297174</recipientCRDNumber>
                <associatedBDName>DeWaay Financial Network, Inc.</associatedBDName>
                <associatedBDCRDNumber>30767</associatedBDCRDNumber>
                <recipientAddress>
                    <street1>13001 University Avenue</street1>
                    <city>Clive</city>
                    <stateOrCountry>IA</stateOrCountry>
                    <stateOrCountryDescription>IOWA</stateOrCountryDescription>
                    <zipCode>50325</zipCode>
                </recipientAddress>
                <statesOfSolicitationList>
                    <state>IA</state>
                    <description>IOWA</description>
                </statesOfSolicitationList>
                <foreignSolicitation>false</foreignSolicitation>
            </recipient>
            <recipient>
                <recipientName>Kristopher F. Etter</recipientName>
                <recipientCRDNumber>4562123</recipientCRDNumber>
                <associatedBDName>IMS Securities, Inc.</associatedBDName>
                <associatedBDCRDNumber>35567</associatedBDCRDNumber>
                <recipientAddress>
                    <street1>5740 Prospect Avenue</street1>
                    <street2>Suite 2000</street2>
                    <city>Dallas</city>
                    <stateOrCountry>TX</stateOrCountry>
                    <stateOrCountryDescription>TEXAS</stateOrCountryDescription>
                    <zipCode>75206</zipCode>
                </recipientAddress>
                <statesOfSolicitationList>
                    <state>TX</state>
                    <description>TEXAS</description>
                </statesOfSolicitationList>
                <foreignSolicitation>false</foreignSolicitation>
            </recipient>
            <recipient>
                <recipientName>Oliver B. Williamson</recipientName>
                <recipientCRDNumber>4642029</recipientCRDNumber>
                <associatedBDName>Calton &amp; Associates, Inc.</associatedBDName>
                <associatedBDCRDNumber>20999</associatedBDCRDNumber>
                <recipientAddress>
                    <street1>611 Hambley Blvd.</street1>
                    <street2>Suite 3</street2>
                    <city>Pikeville</city>
                    <stateOrCountry>KY</stateOrCountry>
                    <stateOrCountryDescription>KENTUCKY</stateOrCountryDescription>
                    <zipCode>41501</zipCode>
                </recipientAddress>
                <statesOfSolicitationList>
                    <state>KY</state>
                    <description>KENTUCKY</description>
                </statesOfSolicitationList>
                <foreignSolicitation>false</foreignSolicitation>
            </recipient>
            <recipient>
                <recipientName>Thomas M. Hille</recipientName>
                <recipientCRDNumber>3070017</recipientCRDNumber>
                <associatedBDName>WFP Securities</associatedBDName>
                <associatedBDCRDNumber>35098</associatedBDCRDNumber>
                <recipientAddress>
                    <street1>689 W. Foothill Blvd.</street1>
                    <street2>Suite D</street2>
                    <city>Claremont</city>
                    <stateOrCountry>CA</stateOrCountry>
                    <stateOrCountryDescription>CALIFORNIA</stateOrCountryDescription>
                    <zipCode>91711</zipCode>
                </recipientAddress>
                <statesOfSolicitationList>
                    <state>CA</state>
                    <description>CALIFORNIA</description>
                </statesOfSolicitationList>
                <foreignSolicitation>false</foreignSolicitation>
            </recipient>
            <recipient>
                <recipientName>James O. Conaway</recipientName>
                <recipientCRDNumber>1920946</recipientCRDNumber>
                <associatedBDName>QA3 Financial Corp.</associatedBDName>
                <associatedBDCRDNumber>14754</associatedBDCRDNumber>
                <recipientAddress>
                    <street1>3000 E. Birch Street</street1>
                    <street2>#109</street2>
                    <city>Brea</city>
                    <stateOrCountry>CA</stateOrCountry>
                    <stateOrCountryDescription>CALIFORNIA</stateOrCountryDescription>
                    <zipCode>92821</zipCode>
                </recipientAddress>
                <statesOfSolicitationList>
                    <state>CA</state>
                    <description>CALIFORNIA</description>
                </statesOfSolicitationList>
                <foreignSolicitation>false</foreignSolicitation>
            </recipient>
            <recipient>
                <recipientName>Tom D. English</recipientName>
                <recipientCRDNumber>2459450</recipientCRDNumber>
                <associatedBDName>WFP Securities</associatedBDName>
                <associatedBDCRDNumber>35098</associatedBDCRDNumber>
                <recipientAddress>
                    <street1>5186 Carroll Canyon Rd.</street1>
                    <city>San Diego</city>
                    <stateOrCountry>CA</stateOrCountry>
                    <stateOrCountryDescription>CALIFORNIA</stateOrCountryDescription>
                    <zipCode>92121</zipCode>
                </recipientAddress>
                <statesOfSolicitationList>
                    <state>CA</state>
                    <description>CALIFORNIA</description>
                </statesOfSolicitationList>
                <foreignSolicitation>false</foreignSolicitation>
            </recipient>
        </salesCompensationList>
        <offeringSalesAmounts>
            <totalOfferingAmount>50000000</totalOfferingAmount>
            <totalAmountSold>525000</totalAmountSold>
            <totalRemaining>49475000</totalRemaining>
            <clarificationOfResponse></clarificationOfResponse>
        </offeringSalesAmounts>
        <investors>
            <hasNonAccreditedInvestors>false</hasNonAccreditedInvestors>
            <totalNumberAlreadyInvested>12</totalNumberAlreadyInvested>
        </investors>
        <salesCommissionsFindersFees>
            <salesCommissions>
                <dollarAmount>47250</dollarAmount>
                <isEstimate>true</isEstimate>
            </salesCommissions>
            <findersFees>
                <dollarAmount>0</dollarAmount>
                <isEstimate>true</isEstimate>
            </findersFees>
            <clarificationOfResponse></clarificationOfResponse>
        </salesCommissionsFindersFees>
        <useOfProceeds>
            <grossProceedsUsed>
                <dollarAmount>0</dollarAmount>
            </grossProceedsUsed>
            <clarificationOfResponse></clarificationOfResponse>
        </useOfProceeds>
        <signatureBlock>
            <authorizedRepresentative>false</authorizedRepresentative>
            <signature>
                <issuerName>Aztec XI-B Oil &amp; Gas LP/Aztec Energy LLC</issuerName>
                <signatureName>Ariane Cox</signatureName>
                <nameOfSigner>Ariane Cox</nameOfSigner>
                <signatureTitle>Vice President and Administrative Coordinator</signatureTitle>
                <signatureDate>2010-12-22</signatureDate>
            </signature>
        </signatureBlock>
    </offeringData>
</edgarSubmission>
