<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with Wdesk from Workiva, formerly WebFilings-->
<!-- -->
<linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <roleRef roleURI="http://naturalgaservices.com/role/BalanceSheets" xlink:href="ngs-20141231.xsd#BalanceSheets" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/BalanceSheetsParenthetical" xlink:href="ngs-20141231.xsd#BalanceSheetsParenthetical" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/CommitmentsAndContingencies" xlink:href="ngs-20141231.xsd#CommitmentsAndContingencies" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/CommitmentsAndContingenciesFutureLeasePaymentsDetails" xlink:href="ngs-20141231.xsd#CommitmentsAndContingenciesFutureLeasePaymentsDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/CommitmentsAndContingenciesNarrativeDetails" xlink:href="ngs-20141231.xsd#CommitmentsAndContingenciesNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/CommitmentsAndContingenciesTables" xlink:href="ngs-20141231.xsd#CommitmentsAndContingenciesTables" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/CreditFacility" xlink:href="ngs-20141231.xsd#CreditFacility" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/CreditFacilityDetails" xlink:href="ngs-20141231.xsd#CreditFacilityDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/DocumentAndEntityInformation" xlink:href="ngs-20141231.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/IncomeTaxes" xlink:href="ngs-20141231.xsd#IncomeTaxes" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/IncomeTaxesComponentsOfDeferredTaxAssetsAndLiabilitiesDetails" xlink:href="ngs-20141231.xsd#IncomeTaxesComponentsOfDeferredTaxAssetsAndLiabilitiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/IncomeTaxesComponentsOfProvisionForIncomeTaxesDetails" xlink:href="ngs-20141231.xsd#IncomeTaxesComponentsOfProvisionForIncomeTaxesDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/IncomeTaxesIncomeTaxReconciliationDetails" xlink:href="ngs-20141231.xsd#IncomeTaxesIncomeTaxReconciliationDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/IncomeTaxesIncomeTaxesTables" xlink:href="ngs-20141231.xsd#IncomeTaxesIncomeTaxesTables" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/IncomeTaxesNarrativeDetails" xlink:href="ngs-20141231.xsd#IncomeTaxesNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/OtherLongTermLiabilities" xlink:href="ngs-20141231.xsd#OtherLongTermLiabilities" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/OtherLongTermLiabilitiesDetails" xlink:href="ngs-20141231.xsd#OtherLongTermLiabilitiesDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/PropertyAndEquipment" xlink:href="ngs-20141231.xsd#PropertyAndEquipment" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/PropertyAndEquipmentDetails" xlink:href="ngs-20141231.xsd#PropertyAndEquipmentDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/PropertyAndEquipmentTables" xlink:href="ngs-20141231.xsd#PropertyAndEquipmentTables" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/QuarterlyFinancialDataUnaudited" xlink:href="ngs-20141231.xsd#QuarterlyFinancialDataUnaudited" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/QuarterlyFinancialDataUnauditedDetails" xlink:href="ngs-20141231.xsd#QuarterlyFinancialDataUnauditedDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/QuarterlyFinancialDataUnauditedTables" xlink:href="ngs-20141231.xsd#QuarterlyFinancialDataUnauditedTables" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/RentalActivity" xlink:href="ngs-20141231.xsd#RentalActivity" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/RentalActivityDetails" xlink:href="ngs-20141231.xsd#RentalActivityDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/RentalActivityTables" xlink:href="ngs-20141231.xsd#RentalActivityTables" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/StatementsOfCashFlows" xlink:href="ngs-20141231.xsd#StatementsOfCashFlows" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/StatementsOfIncome" xlink:href="ngs-20141231.xsd#StatementsOfIncome" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/StatementsOfStockholdersEquity" xlink:href="ngs-20141231.xsd#StatementsOfStockholdersEquity" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/StockBasedCompensation" xlink:href="ngs-20141231.xsd#StockBasedCompensation" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/StockBasedCompensationRestrictedStockActivityDetails" xlink:href="ngs-20141231.xsd#StockBasedCompensationRestrictedStockActivityDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/StockBasedCompensationRestrictedStockNarrativeDetails" xlink:href="ngs-20141231.xsd#StockBasedCompensationRestrictedStockNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/StockBasedCompensationStockOptionActivityDetails" xlink:href="ngs-20141231.xsd#StockBasedCompensationStockOptionActivityDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/StockBasedCompensationStockOptionsByExercisePriceRangeDetails" xlink:href="ngs-20141231.xsd#StockBasedCompensationStockOptionsByExercisePriceRangeDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/StockBasedCompensationStockOptionsNarrativeDetails" xlink:href="ngs-20141231.xsd#StockBasedCompensationStockOptionsNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/StockBasedCompensationSummaryOfUnvestedStockOptionsDetails" xlink:href="ngs-20141231.xsd#StockBasedCompensationSummaryOfUnvestedStockOptionsDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/StockBasedCompensationTables" xlink:href="ngs-20141231.xsd#StockBasedCompensationTables" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/StockBasedCompensationValuationAssumptionsDetails" xlink:href="ngs-20141231.xsd#StockBasedCompensationValuationAssumptionsDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/StockholdersEquity" xlink:href="ngs-20141231.xsd#StockholdersEquity" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/StockholdersEquityDetails" xlink:href="ngs-20141231.xsd#StockholdersEquityDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/SummaryOfSignificantAccountingPolicies" xlink:href="ngs-20141231.xsd#SummaryOfSignificantAccountingPolicies" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/SummaryOfSignificantAccountingPoliciesConcentrationRiskDetails" xlink:href="ngs-20141231.xsd#SummaryOfSignificantAccountingPoliciesConcentrationRiskDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/SummaryOfSignificantAccountingPoliciesIntangiblesDetails" xlink:href="ngs-20141231.xsd#SummaryOfSignificantAccountingPoliciesIntangiblesDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/SummaryOfSignificantAccountingPoliciesNarrativeDetails" xlink:href="ngs-20141231.xsd#SummaryOfSignificantAccountingPoliciesNarrativeDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:href="ngs-20141231.xsd#SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/SummaryOfSignificantAccountingPoliciesPropertyAndEquipmentDetails" xlink:href="ngs-20141231.xsd#SummaryOfSignificantAccountingPoliciesPropertyAndEquipmentDetails" xlink:type="simple" />
  <roleRef roleURI="http://naturalgaservices.com/role/SummaryOfSignificantAccountingPoliciesTables" xlink:href="ngs-20141231.xsd#SummaryOfSignificantAccountingPoliciesTables" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/BalanceSheets" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/BalanceSheetsParenthetical" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/CommitmentsAndContingencies" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/CommitmentsAndContingenciesFutureLeasePaymentsDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/CommitmentsAndContingenciesNarrativeDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/CommitmentsAndContingenciesTables" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/CreditFacility" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/CreditFacilityDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LineOfCreditFacilityTable" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_95F2E0BBE26C51F733FBBD21F1E56A0D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_95F2E0BBE26C51F733FBBD21F1E56A0D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_336517F5E6AF1F1CECD5BD21F1E58192" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_95F2E0BBE26C51F733FBBD21F1E56A0D" xlink:to="loc_us-gaap_RangeAxis_336517F5E6AF1F1CECD5BD21F1E58192" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_0A00B9EAC9E9A765597FBD21F1E5BD6E_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_336517F5E6AF1F1CECD5BD21F1E58192" xlink:to="loc_us-gaap_RangeMember_0A00B9EAC9E9A765597FBD21F1E5BD6E_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_0A00B9EAC9E9A765597FBD21F1E5BD6E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_336517F5E6AF1F1CECD5BD21F1E58192" xlink:to="loc_us-gaap_RangeMember_0A00B9EAC9E9A765597FBD21F1E5BD6E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_15831D8A4D4A088B0912BD21F1E69E63" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_0A00B9EAC9E9A765597FBD21F1E5BD6E" xlink:to="loc_us-gaap_MaximumMember_15831D8A4D4A088B0912BD21F1E69E63" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_268453FADA9595230567BD21F1E69CEF" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_0A00B9EAC9E9A765597FBD21F1E5BD6E" xlink:to="loc_us-gaap_MinimumMember_268453FADA9595230567BD21F1E69CEF" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_ReferenceRateAxis" xlink:label="loc_ngs_ReferenceRateAxis_EB2834EA235316F019C6BD21F1E60BA1" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_95F2E0BBE26C51F733FBBD21F1E56A0D" xlink:to="loc_ngs_ReferenceRateAxis_EB2834EA235316F019C6BD21F1E60BA1" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_ReferenceRateDomain" xlink:label="loc_ngs_ReferenceRateDomain_ECA6C8DB0B1E141E7379BD21F1E66C41_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_ngs_ReferenceRateAxis_EB2834EA235316F019C6BD21F1E60BA1" xlink:to="loc_ngs_ReferenceRateDomain_ECA6C8DB0B1E141E7379BD21F1E66C41_default" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_ReferenceRateDomain" xlink:label="loc_ngs_ReferenceRateDomain_ECA6C8DB0B1E141E7379BD21F1E66C41" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ngs_ReferenceRateAxis_EB2834EA235316F019C6BD21F1E60BA1" xlink:to="loc_ngs_ReferenceRateDomain_ECA6C8DB0B1E141E7379BD21F1E66C41" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LiborBasedRateMember" xlink:label="loc_ngs_LiborBasedRateMember_FDD700019AA81BA9389CBD21F1E697F3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_ReferenceRateDomain_ECA6C8DB0B1E141E7379BD21F1E66C41" xlink:to="loc_ngs_LiborBasedRateMember_FDD700019AA81BA9389CBD21F1E697F3" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_CbFloatingRateMember" xlink:label="loc_ngs_CbFloatingRateMember_75B1BDAECE61F2E3CF3DBD21F1E6688B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_ReferenceRateDomain_ECA6C8DB0B1E141E7379BD21F1E66C41" xlink:to="loc_ngs_CbFloatingRateMember_75B1BDAECE61F2E3CF3DBD21F1E6688B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_607D3414DAE04432A79BBD21F1E6B81B" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_95F2E0BBE26C51F733FBBD21F1E56A0D" xlink:to="loc_us-gaap_CreditFacilityAxis_607D3414DAE04432A79BBD21F1E6B81B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_900A75EB5FDC8C71CB6FBD21F1E6013E_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_607D3414DAE04432A79BBD21F1E6B81B" xlink:to="loc_us-gaap_CreditFacilityDomain_900A75EB5FDC8C71CB6FBD21F1E6013E_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_900A75EB5FDC8C71CB6FBD21F1E6013E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_607D3414DAE04432A79BBD21F1E6B81B" xlink:to="loc_us-gaap_CreditFacilityDomain_900A75EB5FDC8C71CB6FBD21F1E6013E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_2D961E6C1D2E70E911C7BD21F1E64CF1" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_900A75EB5FDC8C71CB6FBD21F1E6013E" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_2D961E6C1D2E70E911C7BD21F1E64CF1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_D208880EDD08A1D46284BD21F1E686CC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_D208880EDD08A1D46284BD21F1E686CC" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LineOfCreditFacilityPotentialMaximumBorrowingCapacity" xlink:label="loc_ngs_LineOfCreditFacilityPotentialMaximumBorrowingCapacity_72B12C7E5D950CE51F37BD21F1E63466" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_ngs_LineOfCreditFacilityPotentialMaximumBorrowingCapacity_72B12C7E5D950CE51F37BD21F1E63466" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LineOfCreditFacilityPotentialIncreaseInBorrowingCapacity" xlink:label="loc_ngs_LineOfCreditFacilityPotentialIncreaseInBorrowingCapacity_815E0D7CAF753672DF64BD21F1E60B77" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_ngs_LineOfCreditFacilityPotentialIncreaseInBorrowingCapacity_815E0D7CAF753672DF64BD21F1E60B77" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LineOfCreditFacilityCurrentBorrowingCapacityComponentPercentageOfEligibleAccountsReceivable" xlink:label="loc_ngs_LineOfCreditFacilityCurrentBorrowingCapacityComponentPercentageOfEligibleAccountsReceivable_841542413183CBF6C0F3BD21F1E60F6C" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_ngs_LineOfCreditFacilityCurrentBorrowingCapacityComponentPercentageOfEligibleAccountsReceivable_841542413183CBF6C0F3BD21F1E60F6C" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LineOfCreditFacilityCurrentBorrowingCapacityComponentPercentageOfEligibleGeneralInventory" xlink:label="loc_ngs_LineOfCreditFacilityCurrentBorrowingCapacityComponentPercentageOfEligibleGeneralInventory_B5FCA4F96092D4361B4CBD21F1E63CA4" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_ngs_LineOfCreditFacilityCurrentBorrowingCapacityComponentPercentageOfEligibleGeneralInventory_B5FCA4F96092D4361B4CBD21F1E63CA4" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LineOfCreditFacilityCurrentBorrowingCapacityAllowableShareOfTotalCommitmentAmountAttributableToGeneralInventoryComponent" xlink:label="loc_ngs_LineOfCreditFacilityCurrentBorrowingCapacityAllowableShareOfTotalCommitmentAmountAttributableToGeneralInventoryComponent_F9EA8FB9E2C0F80EC856BD21F1E6EB56" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_ngs_LineOfCreditFacilityCurrentBorrowingCapacityAllowableShareOfTotalCommitmentAmountAttributableToGeneralInventoryComponent_F9EA8FB9E2C0F80EC856BD21F1E6EB56" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LineOfCreditFacilityCurrentBorrowingCapacityComponentPercentageOfEligibleEquipmentInventory" xlink:label="loc_ngs_LineOfCreditFacilityCurrentBorrowingCapacityComponentPercentageOfEligibleEquipmentInventory_0306005E3B8AF6E55C5FBD21F1E62684" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_ngs_LineOfCreditFacilityCurrentBorrowingCapacityComponentPercentageOfEligibleEquipmentInventory_0306005E3B8AF6E55C5FBD21F1E62684" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_3AF83045A9CC4C3D8946BD21F1E68495" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_3AF83045A9CC4C3D8946BD21F1E68495" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LineOfCreditFacilityReferenceRateNumberOfAllowableBorrowingsOutstanding" xlink:label="loc_ngs_LineOfCreditFacilityReferenceRateNumberOfAllowableBorrowingsOutstanding_83E5379B8A26BADF0363BD21F1E79EFE" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_ngs_LineOfCreditFacilityReferenceRateNumberOfAllowableBorrowingsOutstanding_83E5379B8A26BADF0363BD21F1E79EFE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_66161942AC509A168D36BD21F1E7481A" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_66161942AC509A168D36BD21F1E7481A" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LineofCreditFacilityCommitmentCoverageRatio" xlink:label="loc_ngs_LineofCreditFacilityCommitmentCoverageRatio_0E30E5C919236BF22352BD21F1E72F9B" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_ngs_LineofCreditFacilityCommitmentCoverageRatio_0E30E5C919236BF22352BD21F1E72F9B" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LineofCreditFacilityLeverageRatio" xlink:label="loc_ngs_LineofCreditFacilityLeverageRatio_373BB3C262071A999A1EBD21F1E76A35" xlink:type="locator" />
    <definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_ngs_LineofCreditFacilityLeverageRatio_373BB3C262071A999A1EBD21F1E76A35" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LineOfCreditFacilityDefaultTriggerCertainDefaultsOfOtherCompanyIndebtednessAmount" xlink:label="loc_ngs_LineOfCreditFacilityDefaultTriggerCertainDefaultsOfOtherCompanyIndebtednessAmount_78999FF055EE785C11C0BD21F1E78C6D" xlink:type="locator" />
    <definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_ngs_LineOfCreditFacilityDefaultTriggerCertainDefaultsOfOtherCompanyIndebtednessAmount_78999FF055EE785C11C0BD21F1E78C6D" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LineOfCreditFacilityDefaultTriggerRenderingOfCertainJudgmentsAmount" xlink:label="loc_ngs_LineOfCreditFacilityDefaultTriggerRenderingOfCertainJudgmentsAmount_5BC3196C31DDDE46394DBD21F1E78D73" xlink:type="locator" />
    <definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_ngs_LineOfCreditFacilityDefaultTriggerRenderingOfCertainJudgmentsAmount_5BC3196C31DDDE46394DBD21F1E78D73" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LinesOfCreditCurrent" xlink:label="loc_us-gaap_LinesOfCreditCurrent_A493FBE503F5EFEE0EBBBD21F1E7E046" xlink:type="locator" />
    <definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_us-gaap_LinesOfCreditCurrent_A493FBE503F5EFEE0EBBBD21F1E7E046" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LineOfCreditFacilityInterestRateDuringPeriod" xlink:label="loc_us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_7974D321FA06B66BE7C1BD21F1E7D4A1" xlink:type="locator" />
    <definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_A4C66BD971D09E9135CCBD21F1E649F9" xlink:to="loc_us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_7974D321FA06B66BE7C1BD21F1E7D4A1" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/DocumentAndEntityInformation" xlink:type="extended">
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityInformationLineItems" xlink:label="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:type="locator" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntitiesTable" xlink:label="loc_dei_EntitiesTable_8383ED3F7F15FEF80475BD21F27667A2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_EntitiesTable_8383ED3F7F15FEF80475BD21F27667A2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_48B8E875D6D50BCB1094BD21F276A638" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_8383ED3F7F15FEF80475BD21F27667A2" xlink:to="loc_dei_LegalEntityAxis_48B8E875D6D50BCB1094BD21F276A638" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_FA59BE323821795494F4BD21F27627C8_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_48B8E875D6D50BCB1094BD21F276A638" xlink:to="loc_dei_EntityDomain_FA59BE323821795494F4BD21F27627C8_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_FA59BE323821795494F4BD21F27627C8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_48B8E875D6D50BCB1094BD21F276A638" xlink:to="loc_dei_EntityDomain_FA59BE323821795494F4BD21F27627C8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityRegistrantName" xlink:label="loc_dei_EntityRegistrantName_F5C3CD5DBE764D9AFCD3BD21F276233D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_EntityRegistrantName_F5C3CD5DBE764D9AFCD3BD21F276233D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCentralIndexKey" xlink:label="loc_dei_EntityCentralIndexKey_1B4B83A24DA9A9441188BD21F27694A0" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_EntityCentralIndexKey_1B4B83A24DA9A9441188BD21F27694A0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_CurrentFiscalYearEndDate" xlink:label="loc_dei_CurrentFiscalYearEndDate_2DCF6864F1B8E8DDD842BD21F27721C6" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_CurrentFiscalYearEndDate_2DCF6864F1B8E8DDD842BD21F27721C6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityFilerCategory" xlink:label="loc_dei_EntityFilerCategory_9187C9C7C7DC60E8B58FBD21F2770818" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_EntityFilerCategory_9187C9C7C7DC60E8B58FBD21F2770818" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentType" xlink:label="loc_dei_DocumentType_C4DEBFEBE0AA4954144DBD21F2775477" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_DocumentType_C4DEBFEBE0AA4954144DBD21F2775477" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_2F69A8773DE219072ADABD21F27741D3" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_DocumentPeriodEndDate_2F69A8773DE219072ADABD21F27741D3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentFiscalYearFocus" xlink:label="loc_dei_DocumentFiscalYearFocus_D1A8C0270A29C039CF89BD21F277DDAB" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_DocumentFiscalYearFocus_D1A8C0270A29C039CF89BD21F277DDAB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="loc_dei_DocumentFiscalPeriodFocus_D65287FDB2E40570AD49BD21F2776683" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_DocumentFiscalPeriodFocus_D65287FDB2E40570AD49BD21F2776683" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_AmendmentFlag" xlink:label="loc_dei_AmendmentFlag_A1752F1454F7B643B9E4BD21F2775FE8" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_AmendmentFlag_A1752F1454F7B643B9E4BD21F2775FE8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_8CB35F4E809743072EBCBD21F277DE6A" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_8CB35F4E809743072EBCBD21F277DE6A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityWellKnownSeasonedIssuer" xlink:label="loc_dei_EntityWellKnownSeasonedIssuer_5F0465753FD87CC43F8DBD21F277CD18" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_EntityWellKnownSeasonedIssuer_5F0465753FD87CC43F8DBD21F277CD18" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityVoluntaryFilers" xlink:label="loc_dei_EntityVoluntaryFilers_E26A3AA9857F1560354FBD21F27734D1" xlink:type="locator" />
    <definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_EntityVoluntaryFilers_E26A3AA9857F1560354FBD21F27734D1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityCurrentReportingStatus" xlink:label="loc_dei_EntityCurrentReportingStatus_FC208B9E38FFBAE0A4D2BD21F277EB41" xlink:type="locator" />
    <definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_EntityCurrentReportingStatus_FC208B9E38FFBAE0A4D2BD21F277EB41" xlink:type="arc" />
    <loc xlink:href="http://xbrl.sec.gov/dei/2014/dei-2014-01-31.xsd#dei_EntityPublicFloat" xlink:label="loc_dei_EntityPublicFloat_1D356AB9788E3C866234BD21F2771BFB" xlink:type="locator" />
    <definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_90C8D0349AAECDAD64A4BD21F276AFAF" xlink:to="loc_dei_EntityPublicFloat_1D356AB9788E3C866234BD21F2771BFB" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/IncomeTaxes" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/IncomeTaxesComponentsOfDeferredTaxAssetsAndLiabilitiesDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/IncomeTaxesComponentsOfProvisionForIncomeTaxesDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/IncomeTaxesIncomeTaxReconciliationDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/IncomeTaxesIncomeTaxesTables" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/IncomeTaxesNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLossCarryforwardsLineItems" xlink:label="loc_us-gaap_OperatingLossCarryforwardsLineItems_9040D3A8D66815F25C0CBD21F2185AB1" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLossCarryforwardsTable" xlink:label="loc_us-gaap_OperatingLossCarryforwardsTable_38E8647B2F43052A1E32BD21F218B98A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_9040D3A8D66815F25C0CBD21F2185AB1" xlink:to="loc_us-gaap_OperatingLossCarryforwardsTable_38E8647B2F43052A1E32BD21F218B98A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_DB660FFBCC5131ED4700BD21F218184F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable_38E8647B2F43052A1E32BD21F218B98A" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_DB660FFBCC5131ED4700BD21F218184F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_69FA2971912BB46BC156BD21F2187083_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_DB660FFBCC5131ED4700BD21F218184F" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_69FA2971912BB46BC156BD21F2187083_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_69FA2971912BB46BC156BD21F2187083" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_DB660FFBCC5131ED4700BD21F218184F" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_69FA2971912BB46BC156BD21F2187083" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InternalRevenueServiceIRSMember" xlink:label="loc_us-gaap_InternalRevenueServiceIRSMember_B2CAA350E9E0447ED20DBD21F2180DE0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_69FA2971912BB46BC156BD21F2187083" xlink:to="loc_us-gaap_InternalRevenueServiceIRSMember_B2CAA350E9E0447ED20DBD21F2180DE0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="loc_us-gaap_OperatingLossCarryforwards_3877529A8342CEA34F22BD21F2186116" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_9040D3A8D66815F25C0CBD21F2185AB1" xlink:to="loc_us-gaap_OperatingLossCarryforwards_3877529A8342CEA34F22BD21F2186116" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/OtherLongTermLiabilities" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/OtherLongTermLiabilitiesDetails" xlink:type="extended">
    <loc xlink:href="ngs-20141231.xsd#ngs_OtherLiabilitiesLineItems" xlink:label="loc_ngs_OtherLiabilitiesLineItems_5B9C66854E965FC600AABD21F1F3D015" xlink:type="locator" />
    <loc xlink:href="ngs-20141231.xsd#ngs_ScheduleOfOtherLiabilitiesTable" xlink:label="loc_ngs_ScheduleOfOtherLiabilitiesTable_81B109520A87FB810059BD21F1F20BD0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ngs_OtherLiabilitiesLineItems_5B9C66854E965FC600AABD21F1F3D015" xlink:to="loc_ngs_ScheduleOfOtherLiabilitiesTable_81B109520A87FB810059BD21F1F20BD0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis" xlink:label="loc_us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis_F4C67D2DCEF04547305DBD21F1F2C7E4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ngs_ScheduleOfOtherLiabilitiesTable_81B109520A87FB810059BD21F1F20BD0" xlink:to="loc_us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis_F4C67D2DCEF04547305DBD21F1F2C7E4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain" xlink:label="loc_us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_B59C8838EFE131799407BD21F1F2B287_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis_F4C67D2DCEF04547305DBD21F1F2C7E4" xlink:to="loc_us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_B59C8838EFE131799407BD21F1F2B287_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain" xlink:label="loc_us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_B59C8838EFE131799407BD21F1F2B287" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis_F4C67D2DCEF04547305DBD21F1F2C7E4" xlink:to="loc_us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_B59C8838EFE131799407BD21F1F2B287" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InventoriesMember" xlink:label="loc_us-gaap_InventoriesMember_BF7F7983A22416B8EDCCBD21F1F2659F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermPurchaseCommitmentCategoryOfItemPurchasedDomain_B59C8838EFE131799407BD21F1F2B287" xlink:to="loc_us-gaap_InventoriesMember_BF7F7983A22416B8EDCCBD21F1F2659F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DeferredRevenueNoncurrent" xlink:label="loc_us-gaap_DeferredRevenueNoncurrent_DE499E3476D4DA1A913EBD21F1F36CC6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_OtherLiabilitiesLineItems_5B9C66854E965FC600AABD21F1F3D015" xlink:to="loc_us-gaap_DeferredRevenueNoncurrent_DE499E3476D4DA1A913EBD21F1F36CC6" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_PaymentsToSettleDeferredRevenueLiability" xlink:label="loc_ngs_PaymentsToSettleDeferredRevenueLiability_284031BB3B0209063EFABD21F1F34EBA" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_OtherLiabilitiesLineItems_5B9C66854E965FC600AABD21F1F3D015" xlink:to="loc_ngs_PaymentsToSettleDeferredRevenueLiability_284031BB3B0209063EFABD21F1F34EBA" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_GainLossOnSettlementOfDeferredRevenueLiability" xlink:label="loc_ngs_GainLossOnSettlementOfDeferredRevenueLiability_429881F70B0030325BCABD21F1F3590F" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_OtherLiabilitiesLineItems_5B9C66854E965FC600AABD21F1F3D015" xlink:to="loc_ngs_GainLossOnSettlementOfDeferredRevenueLiability_429881F70B0030325BCABD21F1F3590F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LongTermPurchaseCommitmentAmount" xlink:label="loc_us-gaap_LongTermPurchaseCommitmentAmount_9472D81BB24A25F825AFBD21F1F3A073" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_OtherLiabilitiesLineItems_5B9C66854E965FC600AABD21F1F3D015" xlink:to="loc_us-gaap_LongTermPurchaseCommitmentAmount_9472D81BB24A25F825AFBD21F1F3A073" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LongTermPurchaseCommitmentCashReceivedAsDiscountTowardFuturePurchases" xlink:label="loc_ngs_LongTermPurchaseCommitmentCashReceivedAsDiscountTowardFuturePurchases_6D86A1B8C5DCFECE011ABD21F1F3FEB3" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_OtherLiabilitiesLineItems_5B9C66854E965FC600AABD21F1F3D015" xlink:to="loc_ngs_LongTermPurchaseCommitmentCashReceivedAsDiscountTowardFuturePurchases_6D86A1B8C5DCFECE011ABD21F1F3FEB3" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LongTermPurchaseCommitmentLiabilityRelatedToDeferredDiscount" xlink:label="loc_ngs_LongTermPurchaseCommitmentLiabilityRelatedToDeferredDiscount_351BACBB0E68EF65CFD6BD21F1F3AFDE" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_OtherLiabilitiesLineItems_5B9C66854E965FC600AABD21F1F3D015" xlink:to="loc_ngs_LongTermPurchaseCommitmentLiabilityRelatedToDeferredDiscount_351BACBB0E68EF65CFD6BD21F1F3AFDE" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/PropertyAndEquipment" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/PropertyAndEquipmentDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_971C4ED5BFDE5F68FCE1BD21F1F99D0E" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_B065FC43C0B7423B4DAABD21F1F820B4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_971C4ED5BFDE5F68FCE1BD21F1F99D0E" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_B065FC43C0B7423B4DAABD21F1F820B4" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_F63E294617559EB156FFBD21F1F81078" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_B065FC43C0B7423B4DAABD21F1F820B4" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_F63E294617559EB156FFBD21F1F81078" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_13F9435FD27647EEFCC6BD21F1F8C68A_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_F63E294617559EB156FFBD21F1F81078" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_13F9435FD27647EEFCC6BD21F1F8C68A_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_13F9435FD27647EEFCC6BD21F1F8C68A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_F63E294617559EB156FFBD21F1F81078" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_13F9435FD27647EEFCC6BD21F1F8C68A" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_LandAndBuildingExcludingLeaseholdImprovementsMember" xlink:label="loc_ngs_LandAndBuildingExcludingLeaseholdImprovementsMember_76BCB7DFA9E51656189EBD21F1F80167" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_13F9435FD27647EEFCC6BD21F1F8C68A" xlink:to="loc_ngs_LandAndBuildingExcludingLeaseholdImprovementsMember_76BCB7DFA9E51656189EBD21F1F80167" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_4DC05EB41F4099E4A9E8BD21F1F82393" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_13F9435FD27647EEFCC6BD21F1F8C68A" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_4DC05EB41F4099E4A9E8BD21F1F82393" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_OfficeEquipmentAndFurnitureMember" xlink:label="loc_ngs_OfficeEquipmentAndFurnitureMember_6C8D1ACDFC6C305200F0BD21F1F85781" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_13F9435FD27647EEFCC6BD21F1F8C68A" xlink:to="loc_ngs_OfficeEquipmentAndFurnitureMember_6C8D1ACDFC6C305200F0BD21F1F85781" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:label="loc_us-gaap_ComputerSoftwareIntangibleAssetMember_B1E48B4B96019CA87FE1BD21F1F872CF" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_13F9435FD27647EEFCC6BD21F1F8C68A" xlink:to="loc_us-gaap_ComputerSoftwareIntangibleAssetMember_B1E48B4B96019CA87FE1BD21F1F872CF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_MachineryAndEquipmentMember" xlink:label="loc_us-gaap_MachineryAndEquipmentMember_F26AF52E0B7027525C29BD21F1F83F0A" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_13F9435FD27647EEFCC6BD21F1F8C68A" xlink:to="loc_us-gaap_MachineryAndEquipmentMember_F26AF52E0B7027525C29BD21F1F83F0A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_VehiclesMember" xlink:label="loc_us-gaap_VehiclesMember_8CF4F814172C28670834BD21F1F80484" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_13F9435FD27647EEFCC6BD21F1F8C68A" xlink:to="loc_us-gaap_VehiclesMember_8CF4F814172C28670834BD21F1F80484" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_FCD57A07E8F1167EBACDBD21F1F91BEF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_971C4ED5BFDE5F68FCE1BD21F1F99D0E" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_FCD57A07E8F1167EBACDBD21F1F91BEF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_77612E13EE28F237CC4DBD21F1F92198" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_971C4ED5BFDE5F68FCE1BD21F1F99D0E" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_77612E13EE28F237CC4DBD21F1F92198" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_F9D80FBE323CF21F9504BD21F1F98B1D" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_971C4ED5BFDE5F68FCE1BD21F1F99D0E" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_F9D80FBE323CF21F9504BD21F1F98B1D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_2511A4C466E148AC3191BD21F1F94EFA" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_971C4ED5BFDE5F68FCE1BD21F1F99D0E" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_2511A4C466E148AC3191BD21F1F94EFA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_Depreciation" xlink:label="loc_us-gaap_Depreciation_00733F80FE6E7420DB4CBD21F1F99294" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_971C4ED5BFDE5F68FCE1BD21F1F99D0E" xlink:to="loc_us-gaap_Depreciation_00733F80FE6E7420DB4CBD21F1F99294" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/PropertyAndEquipmentTables" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/QuarterlyFinancialDataUnaudited" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/QuarterlyFinancialDataUnauditedDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/QuarterlyFinancialDataUnauditedTables" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/RentalActivity" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/RentalActivityDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems" xlink:label="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_CDC14FE3A84A6C0A490DBD21F2668D4B" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseByMajorPropertyClassTable" xlink:label="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseByMajorPropertyClassTable_7D7A3A90C2FF013099E5BD21F2665253" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_CDC14FE3A84A6C0A490DBD21F2668D4B" xlink:to="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseByMajorPropertyClassTable_7D7A3A90C2FF013099E5BD21F2665253" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_B1218561117273050970BD21F266B8A4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseByMajorPropertyClassTable_7D7A3A90C2FF013099E5BD21F2665253" xlink:to="loc_us-gaap_RangeAxis_B1218561117273050970BD21F266B8A4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_783A5150D453124B0C80BD21F266792D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_B1218561117273050970BD21F266B8A4" xlink:to="loc_us-gaap_RangeMember_783A5150D453124B0C80BD21F266792D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_783A5150D453124B0C80BD21F266792D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_B1218561117273050970BD21F266B8A4" xlink:to="loc_us-gaap_RangeMember_783A5150D453124B0C80BD21F266792D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_A2D8DB60E604CB30E3F7BD21F2668B62" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_783A5150D453124B0C80BD21F266792D" xlink:to="loc_us-gaap_MinimumMember_A2D8DB60E604CB30E3F7BD21F2668B62" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_8F518D24077CB04ADA0ABD21F2665766" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_783A5150D453124B0C80BD21F266792D" xlink:to="loc_us-gaap_MaximumMember_8F518D24077CB04ADA0ABD21F2665766" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_OperatingLeasesOfLessorOriginalTerm" xlink:label="loc_ngs_OperatingLeasesOfLessorOriginalTerm_9824A832784DAE598B01BD21F266882E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_CDC14FE3A84A6C0A490DBD21F2668D4B" xlink:to="loc_ngs_OperatingLeasesOfLessorOriginalTerm_9824A832784DAE598B01BD21F266882E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableCurrent" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableCurrent_95751A74FAA23FA0FB5BBD21F2669A4C" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_CDC14FE3A84A6C0A490DBD21F2668D4B" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableCurrent_95751A74FAA23FA0FB5BBD21F2669A4C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInTwoYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInTwoYears_D15F66F0D2CFF26A7088BD21F2663468" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_CDC14FE3A84A6C0A490DBD21F2668D4B" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInTwoYears_D15F66F0D2CFF26A7088BD21F2663468" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_OperatingLeasesFutureMinimumPaymentsReceivableAfterTwoYears" xlink:label="loc_ngs_OperatingLeasesFutureMinimumPaymentsReceivableAfterTwoYears_1E1ADE6ADEE2347F64A0BD21F2678E80" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_CDC14FE3A84A6C0A490DBD21F2668D4B" xlink:to="loc_ngs_OperatingLeasesFutureMinimumPaymentsReceivableAfterTwoYears_1E1ADE6ADEE2347F64A0BD21F2678E80" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsReceivable" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsReceivable_09A8228779DBB83D0811BD21F267A0FF" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_CDC14FE3A84A6C0A490DBD21F2668D4B" xlink:to="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsReceivable_09A8228779DBB83D0811BD21F267A0FF" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/RentalActivityTables" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/StatementsOfCashFlows" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_C391F31F7D8EA086AE67EF99F7B89C6F" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_43DA2ABE60305AD65760EF99F7B76E50" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_C391F31F7D8EA086AE67EF99F7B89C6F" xlink:to="loc_us-gaap_StatementTable_43DA2ABE60305AD65760EF99F7B76E50" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="loc_us-gaap_StatementScenarioAxis_2C00BA46EC4EC8A9063AEF99F7B8D8A9" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_43DA2ABE60305AD65760EF99F7B76E50" xlink:to="loc_us-gaap_StatementScenarioAxis_2C00BA46EC4EC8A9063AEF99F7B8D8A9" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_D51C4A088C687C687ADAEF99F7B8ABFB_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementScenarioAxis_2C00BA46EC4EC8A9063AEF99F7B8D8A9" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_D51C4A088C687C687ADAEF99F7B8ABFB_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="loc_us-gaap_ScenarioUnspecifiedDomain_D51C4A088C687C687ADAEF99F7B8ABFB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementScenarioAxis_2C00BA46EC4EC8A9063AEF99F7B8D8A9" xlink:to="loc_us-gaap_ScenarioUnspecifiedDomain_D51C4A088C687C687ADAEF99F7B8ABFB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_DD7BAEA3C9A52725E3EAEF99F7B8E78B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C391F31F7D8EA086AE67EF99F7B89C6F" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_DD7BAEA3C9A52725E3EAEF99F7B8E78B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_943374A3A32AD7E99C3AEF99F7B82870" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_DD7BAEA3C9A52725E3EAEF99F7B8E78B" xlink:to="loc_us-gaap_NetIncomeLoss_943374A3A32AD7E99C3AEF99F7B82870" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_A60FD77B8AF6EC7923EAEF99F7B809CC" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_DD7BAEA3C9A52725E3EAEF99F7B8E78B" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_A60FD77B8AF6EC7923EAEF99F7B809CC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_9B9D786923B45BF68C02EF99F7B8895F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_A60FD77B8AF6EC7923EAEF99F7B809CC" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_9B9D786923B45BF68C02EF99F7B8895F" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_DeferredAndOtherIncomeTaxExpenseBenefit" xlink:label="loc_ngs_DeferredAndOtherIncomeTaxExpenseBenefit_E71AD4AE1D6C7862C7C7EF99F7B838BA" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_A60FD77B8AF6EC7923EAEF99F7B809CC" xlink:to="loc_ngs_DeferredAndOtherIncomeTaxExpenseBenefit_E71AD4AE1D6C7862C7C7EF99F7B838BA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_49AC0A569F3FDCC491C4EF99F7B890F0" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_A60FD77B8AF6EC7923EAEF99F7B809CC" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_49AC0A569F3FDCC491C4EF99F7B890F0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_GainLossOnDispositionOfAssets" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets_5BD3CDE557DA7D95D9D2EF99F7B9AB91" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_A60FD77B8AF6EC7923EAEF99F7B809CC" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets_5BD3CDE557DA7D95D9D2EF99F7B9AB91" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InventoryWriteDown" xlink:label="loc_us-gaap_InventoryWriteDown_C6F48C54B751A059D759EF99F7B94A7C" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_A60FD77B8AF6EC7923EAEF99F7B809CC" xlink:to="loc_us-gaap_InventoryWriteDown_C6F48C54B751A059D759EF99F7B94A7C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_BC8F5702E6764A6A5108EF99F7B9ACA7" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_A60FD77B8AF6EC7923EAEF99F7B809CC" xlink:to="loc_us-gaap_ShareBasedCompensation_BC8F5702E6764A6A5108EF99F7B9ACA7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingAssetsAbstract" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_69C0E4EDA679F6F6B237EF99F7B9632E" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_DD7BAEA3C9A52725E3EAEF99F7B8E78B" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_69C0E4EDA679F6F6B237EF99F7B9632E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_1090F145FB55ECCF87C2EF99F7B9FFB3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_69C0E4EDA679F6F6B237EF99F7B9632E" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_1090F145FB55ECCF87C2EF99F7B9FFB3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_BAD3BD02F8EE77930559EF99F7B9AA01" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_69C0E4EDA679F6F6B237EF99F7B9632E" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_BAD3BD02F8EE77930559EF99F7B9AA01" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_1B9D2BB658ADAB15899DEF99F7B97F80" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingAssetsAbstract_69C0E4EDA679F6F6B237EF99F7B9632E" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_1B9D2BB658ADAB15899DEF99F7B97F80" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingLiabilitiesAbstract" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingLiabilitiesAbstract_3AA032BD556CE664E162EF99F7BAEA56" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_DD7BAEA3C9A52725E3EAEF99F7B8E78B" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingLiabilitiesAbstract_3AA032BD556CE664E162EF99F7BAEA56" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_119E87332DB0D6008F2EEF99F7BAF92D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingLiabilitiesAbstract_3AA032BD556CE664E162EF99F7BAEA56" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_119E87332DB0D6008F2EEF99F7BAF92D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_5E1474D02CE6EDFF6F51EF99F7BA5328" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingLiabilitiesAbstract_3AA032BD556CE664E162EF99F7BAEA56" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_5E1474D02CE6EDFF6F51EF99F7BA5328" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_B0E0DEA0705DC788F128EF99F7BAACF6" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingLiabilitiesAbstract_3AA032BD556CE664E162EF99F7BAEA56" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_B0E0DEA0705DC788F128EF99F7BAACF6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_556ABD5848AF3D159CD7EF99F7BAC020" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingLiabilitiesAbstract_3AA032BD556CE664E162EF99F7BAEA56" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_556ABD5848AF3D159CD7EF99F7BAC020" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities" xlink:label="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities_4BC52FEF69EBAEE6A58CEF99F7BA7BCB" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingLiabilitiesAbstract_3AA032BD556CE664E162EF99F7BAEA56" xlink:to="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationOperatingActivities_4BC52FEF69EBAEE6A58CEF99F7BA7BCB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_10BCB16BCA53E5C6D376EF99F7BA11CD" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_DD7BAEA3C9A52725E3EAEF99F7B8E78B" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_10BCB16BCA53E5C6D376EF99F7BA11CD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_50A3B112216DC8178781EF99F7BAA201" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C391F31F7D8EA086AE67EF99F7B89C6F" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_50A3B112216DC8178781EF99F7BAA201" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_951A6801E7F33E7A6BDDEF99F7BB48A0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_50A3B112216DC8178781EF99F7BAA201" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_951A6801E7F33E7A6BDDEF99F7BB48A0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" xlink:label="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_5C0B23ED750B51529010EF99F7BB7D7B" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_50A3B112216DC8178781EF99F7BAA201" xlink:to="loc_us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_5C0B23ED750B51529010EF99F7BB7D7B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_D735C7F3D86567053735EF99F7BBBF54" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_50A3B112216DC8178781EF99F7BAA201" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_D735C7F3D86567053735EF99F7BBBF54" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_E97B029E9558FD26831FEF99F7BCD326" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C391F31F7D8EA086AE67EF99F7B89C6F" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_E97B029E9558FD26831FEF99F7BCD326" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_ProceedsFromPurchaseCommitmentDiscountNet" xlink:label="loc_ngs_ProceedsFromPurchaseCommitmentDiscountNet_CCAE9E96C161BDF74400EF99F7BC9F79" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_E97B029E9558FD26831FEF99F7BCD326" xlink:to="loc_ngs_ProceedsFromPurchaseCommitmentDiscountNet_CCAE9E96C161BDF74400EF99F7BC9F79" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RepaymentsOfLinesOfCredit" xlink:label="loc_us-gaap_RepaymentsOfLinesOfCredit_7A2A339DA7C356C74441EF99F7BCFE2A" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_E97B029E9558FD26831FEF99F7BCD326" xlink:to="loc_us-gaap_RepaymentsOfLinesOfCredit_7A2A339DA7C356C74441EF99F7BCFE2A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:label="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_6E99B3F28AC69EB18A51EF99F7BCDF80" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_E97B029E9558FD26831FEF99F7BCD326" xlink:to="loc_us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities_6E99B3F28AC69EB18A51EF99F7BCDF80" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_A1BABDEC200FF2354FE5EF99F7BDB562" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_E97B029E9558FD26831FEF99F7BCD326" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_A1BABDEC200FF2354FE5EF99F7BDB562" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_5F028F34326E64281209EF99F7BE5CF2" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_E97B029E9558FD26831FEF99F7BCD326" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_5F028F34326E64281209EF99F7BE5CF2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_37B308EE4C8C8BFB6DF8EF99F7BE56D4" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C391F31F7D8EA086AE67EF99F7B89C6F" xlink:to="loc_us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_37B308EE4C8C8BFB6DF8EF99F7BE56D4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_2EA97D4D708D9690CFCCEF99F7BE7E25" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C391F31F7D8EA086AE67EF99F7B89C6F" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_2EA97D4D708D9690CFCCEF99F7BE7E25" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract_A926CCC01B86D1C8F023EF99F7BF214A" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C391F31F7D8EA086AE67EF99F7B89C6F" xlink:to="loc_us-gaap_SupplementalCashFlowInformationAbstract_A926CCC01B86D1C8F023EF99F7BF214A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InterestPaid" xlink:label="loc_us-gaap_InterestPaid_C49B118668A3A37CE568EF99F7BF53C5" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_A926CCC01B86D1C8F023EF99F7BF214A" xlink:to="loc_us-gaap_InterestPaid_C49B118668A3A37CE568EF99F7BF53C5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncomeTaxesPaid" xlink:label="loc_us-gaap_IncomeTaxesPaid_940D8D13E1EFCB7E21C5EF99F7C0169D" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_A926CCC01B86D1C8F023EF99F7BF214A" xlink:to="loc_us-gaap_IncomeTaxesPaid_940D8D13E1EFCB7E21C5EF99F7C0169D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:label="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_643863DDC2EC30FA68C4EF99F7C0BF1F" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_C391F31F7D8EA086AE67EF99F7B89C6F" xlink:to="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_643863DDC2EC30FA68C4EF99F7C0BF1F" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_TransferOfRentalEquipmentToInventory" xlink:label="loc_ngs_TransferOfRentalEquipmentToInventory_8C0CF602F34178AF061FEF99F7C135BD" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_643863DDC2EC30FA68C4EF99F7C0BF1F" xlink:to="loc_ngs_TransferOfRentalEquipmentToInventory_8C0CF602F34178AF061FEF99F7C135BD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:label="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_64748D3A26930B6E3D94EFD5FEBB2BC8" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_643863DDC2EC30FA68C4EF99F7C0BF1F" xlink:to="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_64748D3A26930B6E3D94EFD5FEBB2BC8" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/StatementsOfIncome" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/StatementsOfStockholdersEquity" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_AF0FE489815BC2C1E93509E0112E2254" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_C2890E40FF4983B7AF1609E0112EFFAF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_AF0FE489815BC2C1E93509E0112E2254" xlink:to="loc_us-gaap_StatementTable_C2890E40FF4983B7AF1609E0112EFFAF" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_FBE9EAD009075C4BF96C09E0112E3405" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_C2890E40FF4983B7AF1609E0112EFFAF" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_FBE9EAD009075C4BF96C09E0112E3405" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_E29B28636987A64D48FD09E0112E51DE_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_FBE9EAD009075C4BF96C09E0112E3405" xlink:to="loc_us-gaap_EquityComponentDomain_E29B28636987A64D48FD09E0112E51DE_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_E29B28636987A64D48FD09E0112E51DE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_FBE9EAD009075C4BF96C09E0112E3405" xlink:to="loc_us-gaap_EquityComponentDomain_E29B28636987A64D48FD09E0112E51DE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PreferredStockMember" xlink:label="loc_us-gaap_PreferredStockMember_36E1A9D0E89A3605F9B109E0112E1086" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_E29B28636987A64D48FD09E0112E51DE" xlink:to="loc_us-gaap_PreferredStockMember_36E1A9D0E89A3605F9B109E0112E1086" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_F5CAC28EBDE2778CE87509E0112E70CD" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_E29B28636987A64D48FD09E0112E51DE" xlink:to="loc_us-gaap_CommonStockMember_F5CAC28EBDE2778CE87509E0112E70CD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_F9991B1E0368F738185809E0112E3272" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_E29B28636987A64D48FD09E0112E51DE" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_F9991B1E0368F738185809E0112E3272" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_F1530141B6491A5C0F6A09E0112E7C5C" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_E29B28636987A64D48FD09E0112E51DE" xlink:to="loc_us-gaap_RetainedEarningsMember_F1530141B6491A5C0F6A09E0112E7C5C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0885E241699091DF8EB309E0112E19C8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_AF0FE489815BC2C1E93509E0112E2254" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0885E241699091DF8EB309E0112E19C8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_DD126D1D0044B146ABE809E0112F7A4C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0885E241699091DF8EB309E0112E19C8" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_DD126D1D0044B146ABE809E0112F7A4C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_DAA2168D0379C7D2E2AC09E0112F7653" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0885E241699091DF8EB309E0112E19C8" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_DAA2168D0379C7D2E2AC09E0112F7653" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_549919836DE693FB02E709E0112FDE22" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0885E241699091DF8EB309E0112E19C8" xlink:to="loc_us-gaap_StockholdersEquity_549919836DE693FB02E709E0112FDE22" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_872792056AC5FEEB16AC09E0112F2E16" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0885E241699091DF8EB309E0112E19C8" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_872792056AC5FEEB16AC09E0112F2E16" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_5D5AB687B778FEC8BE2F09E0112F28FF" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0885E241699091DF8EB309E0112E19C8" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_5D5AB687B778FEC8BE2F09E0112F28FF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_7F3F00F5131F4C74FF0409E0112F8A28" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0885E241699091DF8EB309E0112E19C8" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_7F3F00F5131F4C74FF0409E0112F8A28" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_4EB8DEF7E411F5EF309809E01130C8AA" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0885E241699091DF8EB309E0112E19C8" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_4EB8DEF7E411F5EF309809E01130C8AA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross_8C256869602907C4AB1909E01130E5B7" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0885E241699091DF8EB309E0112E19C8" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross_8C256869602907C4AB1909E01130E5B7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation_F2974F01CF6AE34D4F2B09E01130F2A4" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0885E241699091DF8EB309E0112E19C8" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation_F2974F01CF6AE34D4F2B09E01130F2A4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition_C356A73CEDF62B373AC909E01130DFFB" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0885E241699091DF8EB309E0112E19C8" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalShareBasedCompensationRestrictedStockUnitsRequisiteServicePeriodRecognition_C356A73CEDF62B373AC909E01130DFFB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_E095FC21FEB2F47FF75809E01130D14B" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0885E241699091DF8EB309E0112E19C8" xlink:to="loc_us-gaap_NetIncomeLoss_E095FC21FEB2F47FF75809E01130D14B" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/StockBasedCompensation" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/StockBasedCompensationRestrictedStockActivityDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_67D93DED690B09980185BD21F194B33B" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EBBFFC0DD1207FE0AD97BD21F193F1FE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_67D93DED690B09980185BD21F194B33B" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EBBFFC0DD1207FE0AD97BD21F193F1FE" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_81E04C72F1EABBA373A0BD21F19310C7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EBBFFC0DD1207FE0AD97BD21F193F1FE" xlink:to="loc_us-gaap_AwardTypeAxis_81E04C72F1EABBA373A0BD21F19310C7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_EAB1EC8ADF90FCFCD270BD21F193B5DF_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_81E04C72F1EABBA373A0BD21F19310C7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_EAB1EC8ADF90FCFCD270BD21F193B5DF_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_EAB1EC8ADF90FCFCD270BD21F193B5DF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_81E04C72F1EABBA373A0BD21F19310C7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_EAB1EC8ADF90FCFCD270BD21F193B5DF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="loc_us-gaap_RestrictedStockMember_C7103AAA27A4D4BEA442BD21F1949C41" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_EAB1EC8ADF90FCFCD270BD21F193B5DF" xlink:to="loc_us-gaap_RestrictedStockMember_C7103AAA27A4D4BEA442BD21F1949C41" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_2CF43F24E4847934FBA3BD21F19403B7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_67D93DED690B09980185BD21F194B33B" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_2CF43F24E4847934FBA3BD21F19403B7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_9F5901C7DCB259B6BC1CBD21F194FE0D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_2CF43F24E4847934FBA3BD21F19403B7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_9F5901C7DCB259B6BC1CBD21F194FE0D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_1F3385C531AE04D5001ABD21F1945C1D" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_2CF43F24E4847934FBA3BD21F19403B7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_1F3385C531AE04D5001ABD21F1945C1D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_2EC5255EA52514AA9740BD21F1944EDE" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_2CF43F24E4847934FBA3BD21F19403B7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_2EC5255EA52514AA9740BD21F1944EDE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_78836208E3C82C9C0BBABD21F1949296" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_2CF43F24E4847934FBA3BD21F19403B7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_78836208E3C82C9C0BBABD21F1949296" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_BE48FD338649602CFD7EBD21F1948CE1" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_67D93DED690B09980185BD21F194B33B" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_BE48FD338649602CFD7EBD21F1948CE1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_C27FA00A72CB7D7E0655BD21F19420AB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_BE48FD338649602CFD7EBD21F1948CE1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_C27FA00A72CB7D7E0655BD21F19420AB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_72E4658818B6848ABBE6BD21F194A630" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_BE48FD338649602CFD7EBD21F1948CE1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_72E4658818B6848ABBE6BD21F194A630" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_A8C16874C5585B015A41BD21F194A606" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_BE48FD338649602CFD7EBD21F1948CE1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_A8C16874C5585B015A41BD21F194A606" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_7802C6A3B6D98840D009BD21F194AAF7" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_BE48FD338649602CFD7EBD21F1948CE1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_7802C6A3B6D98840D009BD21F194AAF7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_286FE0AE0B309CBE892BBD21F194BB4D" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_67D93DED690B09980185BD21F194B33B" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_286FE0AE0B309CBE892BBD21F194BB4D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageRemainingContractualTerms" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageRemainingContractualTerms_4053FC1AAA692EF8DE56BD21F1958685" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_286FE0AE0B309CBE892BBD21F194BB4D" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsOutstandingWeightedAverageRemainingContractualTerms_4053FC1AAA692EF8DE56BD21F1958685" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueAbstract" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueAbstract_B21792325E41E5733E06BD21F1952D40" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_67D93DED690B09980185BD21F194B33B" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueAbstract_B21792325E41E5733E06BD21F1952D40" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding_2D519C9AEEC3B6F29B5CBD21F195FFFF" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueAbstract_B21792325E41E5733E06BD21F1952D40" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding_2D519C9AEEC3B6F29B5CBD21F195FFFF" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateIntrinsicValueGrantsinPeriod" xlink:label="loc_ngs_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateIntrinsicValueGrantsinPeriod_DC1CBB8BFB369669F8B3BD21F195CF66" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueAbstract_B21792325E41E5733E06BD21F1952D40" xlink:to="loc_ngs_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherthanOptionsAggregateIntrinsicValueGrantsinPeriod_DC1CBB8BFB369669F8B3BD21F195CF66" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueVested" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueVested_673B35E59AF4FA4C3C6DBD21F1959E58" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueAbstract_B21792325E41E5733E06BD21F1952D40" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueVested_673B35E59AF4FA4C3C6DBD21F1959E58" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/StockBasedCompensationRestrictedStockNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1FBFDC693C975A3154C71318E77FA393" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_79D6403DD43950AB5FFE1318E77E4B13" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1FBFDC693C975A3154C71318E77FA393" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_79D6403DD43950AB5FFE1318E77E4B13" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_A1E1D9BA3FFBF8E46C2F1318E77E84B6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_79D6403DD43950AB5FFE1318E77E4B13" xlink:to="loc_us-gaap_PlanNameAxis_A1E1D9BA3FFBF8E46C2F1318E77E84B6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_864A0AAFE142D21B77E41318E77EF0FC_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_A1E1D9BA3FFBF8E46C2F1318E77E84B6" xlink:to="loc_us-gaap_PlanNameDomain_864A0AAFE142D21B77E41318E77EF0FC_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_864A0AAFE142D21B77E41318E77EF0FC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_A1E1D9BA3FFBF8E46C2F1318E77E84B6" xlink:to="loc_us-gaap_PlanNameDomain_864A0AAFE142D21B77E41318E77EF0FC" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_TwoThousandNineRestrictedStockUnitsPlanMember" xlink:label="loc_ngs_TwoThousandNineRestrictedStockUnitsPlanMember_8B4EB55836B35F111B291318E77E9541" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_864A0AAFE142D21B77E41318E77EF0FC" xlink:to="loc_ngs_TwoThousandNineRestrictedStockUnitsPlanMember_8B4EB55836B35F111B291318E77E9541" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_TitleOfIndividualAxis" xlink:label="loc_us-gaap_TitleOfIndividualAxis_297551C761DC02610C041318E77E8419" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_79D6403DD43950AB5FFE1318E77E4B13" xlink:to="loc_us-gaap_TitleOfIndividualAxis_297551C761DC02610C041318E77E8419" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_8CCA18BC4FFF0FE60BD21318E77EC474_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TitleOfIndividualAxis_297551C761DC02610C041318E77E8419" xlink:to="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_8CCA18BC4FFF0FE60BD21318E77EC474_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_8CCA18BC4FFF0FE60BD21318E77EC474" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TitleOfIndividualAxis_297551C761DC02610C041318E77E8419" xlink:to="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_8CCA18BC4FFF0FE60BD21318E77EC474" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ChiefFinancialOfficerMember" xlink:label="loc_us-gaap_ChiefFinancialOfficerMember_2C7368F54708CC039FAC1318E77F8F28" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_8CCA18BC4FFF0FE60BD21318E77EC474" xlink:to="loc_us-gaap_ChiefFinancialOfficerMember_2C7368F54708CC039FAC1318E77F8F28" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_VicePresidentofTechnicalServicesMember" xlink:label="loc_ngs_VicePresidentofTechnicalServicesMember_7E1EFB9AAC414D7174D81318E77F5188" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_8CCA18BC4FFF0FE60BD21318E77EC474" xlink:to="loc_ngs_VicePresidentofTechnicalServicesMember_7E1EFB9AAC414D7174D81318E77F5188" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ExecutiveOfficerMember" xlink:label="loc_us-gaap_ExecutiveOfficerMember_80B87168657BC178615C1318E77FE544" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_8CCA18BC4FFF0FE60BD21318E77EC474" xlink:to="loc_us-gaap_ExecutiveOfficerMember_80B87168657BC178615C1318E77FE544" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DirectorMember" xlink:label="loc_us-gaap_DirectorMember_ABE7D81A3C02330863671318E77FEDD8" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_8CCA18BC4FFF0FE60BD21318E77EC474" xlink:to="loc_us-gaap_DirectorMember_ABE7D81A3C02330863671318E77FEDD8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ChiefExecutiveOfficerMember" xlink:label="loc_us-gaap_ChiefExecutiveOfficerMember_73EF3A3BB62993973C8F1318E77F9DC0" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_8CCA18BC4FFF0FE60BD21318E77EC474" xlink:to="loc_us-gaap_ChiefExecutiveOfficerMember_73EF3A3BB62993973C8F1318E77F9DC0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_3B4C6D802327E3FDA8A81318E77F110C" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_79D6403DD43950AB5FFE1318E77E4B13" xlink:to="loc_us-gaap_AwardTypeAxis_3B4C6D802327E3FDA8A81318E77F110C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CE842F9F6E4C8BF509D11318E77F1B3E_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_3B4C6D802327E3FDA8A81318E77F110C" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CE842F9F6E4C8BF509D11318E77F1B3E_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CE842F9F6E4C8BF509D11318E77F1B3E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_3B4C6D802327E3FDA8A81318E77F110C" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CE842F9F6E4C8BF509D11318E77F1B3E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="loc_us-gaap_RestrictedStockMember_C5E15DBFB69B5949D1891318E77FFD12" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_CE842F9F6E4C8BF509D11318E77F1B3E" xlink:to="loc_us-gaap_RestrictedStockMember_C5E15DBFB69B5949D1891318E77FFD12" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_AAF01CBB5FC75D9124531318E77FF63C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1FBFDC693C975A3154C71318E77FA393" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_AAF01CBB5FC75D9124531318E77FF63C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_8AA8B97679F9DF5BCF781318E780404F" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1FBFDC693C975A3154C71318E77FA393" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_8AA8B97679F9DF5BCF781318E780404F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_18939326EBF1499217B11318E78008CC" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1FBFDC693C975A3154C71318E77FA393" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_18939326EBF1499217B11318E78008CC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_3CB256EEFBBAAE2E617E1318E780A342" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1FBFDC693C975A3154C71318E77FA393" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_3CB256EEFBBAAE2E617E1318E780A342" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_851608F739D22E79F93F1318E780ECC5" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1FBFDC693C975A3154C71318E77FA393" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_851608F739D22E79F93F1318E780ECC5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_4E44E173FCDC5A6843521318E7809EAC" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1FBFDC693C975A3154C71318E77FA393" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_4E44E173FCDC5A6843521318E7809EAC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_D63BEF35E234009EF1F21318E7807549" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1FBFDC693C975A3154C71318E77FA393" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_D63BEF35E234009EF1F21318E7807549" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberofRemainingSharesAuthorized" xlink:label="loc_ngs_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberofRemainingSharesAuthorized_B02D1E6AB6E2EAF01B541318E780FD8E" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1FBFDC693C975A3154C71318E77FA393" xlink:to="loc_ngs_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberofRemainingSharesAuthorized_B02D1E6AB6E2EAF01B541318E780FD8E" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/StockBasedCompensationStockOptionActivityDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6E254965425EEC30AE680046954AAEA0" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_AAA1FD0280F2C90CD5560046954A52AB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6E254965425EEC30AE680046954AAEA0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_AAA1FD0280F2C90CD5560046954A52AB" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_5766364F95AE55A6731A0046954A1FAE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_AAA1FD0280F2C90CD5560046954A52AB" xlink:to="loc_us-gaap_AwardTypeAxis_5766364F95AE55A6731A0046954A1FAE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9CDFB22DE6A729CBBD680046954A51BC_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_5766364F95AE55A6731A0046954A1FAE" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9CDFB22DE6A729CBBD680046954A51BC_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9CDFB22DE6A729CBBD680046954A51BC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_5766364F95AE55A6731A0046954A1FAE" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9CDFB22DE6A729CBBD680046954A51BC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_613C74253B5D0C319CB70046954AB843" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9CDFB22DE6A729CBBD680046954A51BC" xlink:to="loc_us-gaap_EmployeeStockOptionMember_613C74253B5D0C319CB70046954AB843" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_E8A55D0929EECD8B856F0046954AE46E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6E254965425EEC30AE680046954AAEA0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_E8A55D0929EECD8B856F0046954AE46E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_134FDAED3C877EC7C9180046954AC499" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_E8A55D0929EECD8B856F0046954AE46E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_134FDAED3C877EC7C9180046954AC499" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_BB927E89AB39C1258EA40046954A2A41" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_E8A55D0929EECD8B856F0046954AE46E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_BB927E89AB39C1258EA40046954A2A41" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_F07353D53174ADEE3AD80046954A4990" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_E8A55D0929EECD8B856F0046954AE46E" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_F07353D53174ADEE3AD80046954A4990" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_616E2F0E2C258EA6057B0046954A5F2D" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_E8A55D0929EECD8B856F0046954AE46E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_616E2F0E2C258EA6057B0046954A5F2D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod_F8FD4C4F59946B1358E70046954A6F8F" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_E8A55D0929EECD8B856F0046954AE46E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod_F8FD4C4F59946B1358E70046954A6F8F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_031A7EDB49220940686C0046954B54D8" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6E254965425EEC30AE680046954AAEA0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_031A7EDB49220940686C0046954B54D8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_C3E9CC76EEB2FB75F3540046954BC363" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6E254965425EEC30AE680046954AAEA0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_C3E9CC76EEB2FB75F3540046954BC363" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_52B506556BD242FAD28D0046954B08B8" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_C3E9CC76EEB2FB75F3540046954BC363" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_52B506556BD242FAD28D0046954B08B8" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_F62A342C79B0772F151C0046954BA49A" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_C3E9CC76EEB2FB75F3540046954BC363" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_F62A342C79B0772F151C0046954BA49A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_683725FC140F8C721A500046954BE649" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_C3E9CC76EEB2FB75F3540046954BC363" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_683725FC140F8C721A500046954BE649" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_1A274B0C1647F057ACF20046954B4FA3" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_C3E9CC76EEB2FB75F3540046954BC363" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_1A274B0C1647F057ACF20046954B4FA3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice_D7C6DC01A204962A100E0046954B690F" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_C3E9CC76EEB2FB75F3540046954BC363" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice_D7C6DC01A204962A100E0046954B690F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_DD23A0943E6BC2614D660046954B7CDA" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6E254965425EEC30AE680046954AAEA0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_DD23A0943E6BC2614D660046954B7CDA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_1AA926BD3F4EFA178E6C0046954BF430" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6E254965425EEC30AE680046954AAEA0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_1AA926BD3F4EFA178E6C0046954BF430" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" xlink:label="loc_ngs_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract_955B8521A4B395B4EDC40046954BD0DF" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6E254965425EEC30AE680046954AAEA0" xlink:to="loc_ngs_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract_955B8521A4B395B4EDC40046954BD0DF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_CE6D3ED31A0AFEEA36900046954B47AD" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract_955B8521A4B395B4EDC40046954BD0DF" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_CE6D3ED31A0AFEEA36900046954B47AD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_924860CFEF8DC1A8020F0046954BFEAF" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract_955B8521A4B395B4EDC40046954BD0DF" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_924860CFEF8DC1A8020F0046954BFEAF" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsIntrinsicValueRollForward" xlink:label="loc_ngs_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsIntrinsicValueRollForward_AA14231806711CAD3D790046954B2BF6" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6E254965425EEC30AE680046954AAEA0" xlink:to="loc_ngs_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsIntrinsicValueRollForward_AA14231806711CAD3D790046954B2BF6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_786895E8C02C0FC453990046954B05B2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsIntrinsicValueRollForward_AA14231806711CAD3D790046954B2BF6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_786895E8C02C0FC453990046954B05B2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_7FE23B4366CC03B8A46D0046954CF4F7" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsIntrinsicValueRollForward_AA14231806711CAD3D790046954B2BF6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_7FE23B4366CC03B8A46D0046954CF4F7" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_SharebasedCompensationArrangementbySharebasedPaymentAwardOptionsForfeitedinPeriodIntrinsicValue" xlink:label="loc_ngs_SharebasedCompensationArrangementbySharebasedPaymentAwardOptionsForfeitedinPeriodIntrinsicValue_1C19DD7C6176163C7598004696588799" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsIntrinsicValueRollForward_AA14231806711CAD3D790046954B2BF6" xlink:to="loc_ngs_SharebasedCompensationArrangementbySharebasedPaymentAwardOptionsForfeitedinPeriodIntrinsicValue_1C19DD7C6176163C7598004696588799" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_E76732D176F0085303E00046954C443E" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsIntrinsicValueRollForward_AA14231806711CAD3D790046954B2BF6" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_E76732D176F0085303E00046954C443E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_472D674045833CC6BC450046954C9E15" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6E254965425EEC30AE680046954AAEA0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_472D674045833CC6BC450046954C9E15" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/StockBasedCompensationStockOptionsByExercisePriceRangeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_62DAF538F23A1C2D575F1318C5325EB0" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_2833EEC7B2111CB55BDE1318C531ACF4" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_62DAF538F23A1C2D575F1318C5325EB0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_2833EEC7B2111CB55BDE1318C531ACF4" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_FFF6FF165FED318907C51318C5329019" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_2833EEC7B2111CB55BDE1318C531ACF4" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_FFF6FF165FED318907C51318C5329019" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_48DE4067AB5067E5775C1318C53282C2_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_FFF6FF165FED318907C51318C5329019" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_48DE4067AB5067E5775C1318C53282C2_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_48DE4067AB5067E5775C1318C53282C2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_FFF6FF165FED318907C51318C5329019" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_48DE4067AB5067E5775C1318C53282C2" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_RangeTwoMember" xlink:label="loc_ngs_RangeTwoMember_87A494CBFFDDACEC78631318C532F2E7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_48DE4067AB5067E5775C1318C53282C2" xlink:to="loc_ngs_RangeTwoMember_87A494CBFFDDACEC78631318C532F2E7" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_RangeThreeMember" xlink:label="loc_ngs_RangeThreeMember_DC3C431016ABD7FB3F7C1318C53235AF" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_48DE4067AB5067E5775C1318C53282C2" xlink:to="loc_ngs_RangeThreeMember_DC3C431016ABD7FB3F7C1318C53235AF" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_RangeFourMember" xlink:label="loc_ngs_RangeFourMember_B560B2082F6CFAA2F7DA1318C532AD74" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_48DE4067AB5067E5775C1318C53282C2" xlink:to="loc_ngs_RangeFourMember_B560B2082F6CFAA2F7DA1318C532AD74" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_RangeFiveMember" xlink:label="loc_ngs_RangeFiveMember_50A04B1009CB3F8F65471318C5328F99" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_48DE4067AB5067E5775C1318C53282C2" xlink:to="loc_ngs_RangeFiveMember_50A04B1009CB3F8F65471318C5328F99" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_07D8CD2A7B534A7EE2241318C532D1A3" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_62DAF538F23A1C2D575F1318C5325EB0" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_07D8CD2A7B534A7EE2241318C532D1A3" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2_00B8BCA257A3CA7FD3F51318C533E4B7" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_62DAF538F23A1C2D575F1318C5325EB0" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2_00B8BCA257A3CA7FD3F51318C533E4B7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_52222EC3FAA43CF241391318C533B245" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_62DAF538F23A1C2D575F1318C5325EB0" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1_52222EC3FAA43CF241391318C533B245" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_36B6AACDC6A6327162131318C53387BF" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_62DAF538F23A1C2D575F1318C5325EB0" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_36B6AACDC6A6327162131318C53387BF" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:label="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_1BF6E446B624601D496D1318C533342E" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_62DAF538F23A1C2D575F1318C5325EB0" xlink:to="loc_us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_1BF6E446B624601D496D1318C533342E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_40565B99194CCABE5F7B1318C533F8CE" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_62DAF538F23A1C2D575F1318C5325EB0" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_40565B99194CCABE5F7B1318C533F8CE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_BB63D487F6FF8034122D1318C53365A5" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_62DAF538F23A1C2D575F1318C5325EB0" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_BB63D487F6FF8034122D1318C53365A5" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/StockBasedCompensationStockOptionsNarrativeDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EA29552B50F47E07A2A5F06151F82306" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EA29552B50F47E07A2A5F06151F82306" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_TitleOfIndividualAxis" xlink:label="loc_us-gaap_TitleOfIndividualAxis_6189FA047B3408F3E9ACF06151F8B329" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EA29552B50F47E07A2A5F06151F82306" xlink:to="loc_us-gaap_TitleOfIndividualAxis_6189FA047B3408F3E9ACF06151F8B329" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_F9FAD9C474177EA89BDAF06151F82A0D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TitleOfIndividualAxis_6189FA047B3408F3E9ACF06151F8B329" xlink:to="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_F9FAD9C474177EA89BDAF06151F82A0D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_F9FAD9C474177EA89BDAF06151F82A0D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TitleOfIndividualAxis_6189FA047B3408F3E9ACF06151F8B329" xlink:to="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_F9FAD9C474177EA89BDAF06151F82A0D" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_NonExecutiveEmployeesMember" xlink:label="loc_ngs_NonExecutiveEmployeesMember_A5F5FEF588AC0CF653D6F06151F88BCC" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TitleOfIndividualWithRelationshipToEntityDomain_F9FAD9C474177EA89BDAF06151F82A0D" xlink:to="loc_ngs_NonExecutiveEmployeesMember_A5F5FEF588AC0CF653D6F06151F88BCC" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_9EF94A7325AE2BAB748DF06151F8952E" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EA29552B50F47E07A2A5F06151F82306" xlink:to="loc_us-gaap_AwardTypeAxis_9EF94A7325AE2BAB748DF06151F8952E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_E1531670EB83B44BDDCEF06151F8ED8B_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_9EF94A7325AE2BAB748DF06151F8952E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_E1531670EB83B44BDDCEF06151F8ED8B_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_E1531670EB83B44BDDCEF06151F8ED8B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_9EF94A7325AE2BAB748DF06151F8952E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_E1531670EB83B44BDDCEF06151F8ED8B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_EF587617AE72CF5C29CCF06151F8978F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_E1531670EB83B44BDDCEF06151F8ED8B" xlink:to="loc_us-gaap_EmployeeStockOptionMember_EF587617AE72CF5C29CCF06151F8978F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_4D97B9EDA9355FE13037F06151F804E4" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EA29552B50F47E07A2A5F06151F82306" xlink:to="loc_us-gaap_StatementClassOfStockAxis_4D97B9EDA9355FE13037F06151F804E4" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_EF9F8306BAB8B374D97EF06151F946BA_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_4D97B9EDA9355FE13037F06151F804E4" xlink:to="loc_us-gaap_ClassOfStockDomain_EF9F8306BAB8B374D97EF06151F946BA_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_EF9F8306BAB8B374D97EF06151F946BA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_4D97B9EDA9355FE13037F06151F804E4" xlink:to="loc_us-gaap_ClassOfStockDomain_EF9F8306BAB8B374D97EF06151F946BA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_5C67192781BDC91B46FBF06151F989C0" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_EF9F8306BAB8B374D97EF06151F946BA" xlink:to="loc_us-gaap_CommonStockMember_5C67192781BDC91B46FBF06151F989C0" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_889DE5974B43C046692CF06151F96D1B" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_EA29552B50F47E07A2A5F06151F82306" xlink:to="loc_us-gaap_PlanNameAxis_889DE5974B43C046692CF06151F96D1B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_464853C3A97440055565F06151F9A245_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_889DE5974B43C046692CF06151F96D1B" xlink:to="loc_us-gaap_PlanNameDomain_464853C3A97440055565F06151F9A245_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_464853C3A97440055565F06151F9A245" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_889DE5974B43C046692CF06151F96D1B" xlink:to="loc_us-gaap_PlanNameDomain_464853C3A97440055565F06151F9A245" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_A1998StockOptionPlanMember" xlink:label="loc_ngs_A1998StockOptionPlanMember_FB69CCD55BCE0D9D816FF06151F9B70C" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_464853C3A97440055565F06151F9A245" xlink:to="loc_ngs_A1998StockOptionPlanMember_FB69CCD55BCE0D9D816FF06151F9B70C" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_SharebasedCompensationArrangementbySharebasedPaymentAwardOptionsNumberofOptionsGranted" xlink:label="loc_ngs_SharebasedCompensationArrangementbySharebasedPaymentAwardOptionsNumberofOptionsGranted_4678B120F52251D029BAF064633FFF70" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_ngs_SharebasedCompensationArrangementbySharebasedPaymentAwardOptionsNumberofOptionsGranted_4678B120F52251D029BAF064633FFF70" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_9F98CEA85CBA1CD08A24F06151F9117D" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_9F98CEA85CBA1CD08A24F06151F9117D" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_55889B3D5EB5064A7DA8F06151F9F102" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_55889B3D5EB5064A7DA8F06151F9F102" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_35E4EB13CFA83F5DCE5FF06151F96077" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_35E4EB13CFA83F5DCE5FF06151F96077" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_348A2A17B7CD8F274EA5F06151F98008" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_348A2A17B7CD8F274EA5F06151F98008" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_E94BF3D0286989D7B94DF06151F9077A" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_E94BF3D0286989D7B94DF06151F9077A" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_36ECC9090D82FF1C9842F06151F9BA33" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_36ECC9090D82FF1C9842F06151F9BA33" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_55C53BC3A031305F2C74F06151F92F99" xlink:type="locator" />
    <definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_55C53BC3A031305F2C74F06151F92F99" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_06917EC6239F02DEDBD2F06151F94F20" xlink:type="locator" />
    <definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_06917EC6239F02DEDBD2F06151F94F20" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_3DB0FF609127A73B8E1AF06151F9B874" xlink:type="locator" />
    <definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_3DB0FF609127A73B8E1AF06151F9B874" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_573818BC6D4FA8D2F2BEF06151FA8BDD" xlink:type="locator" />
    <definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_573818BC6D4FA8D2F2BEF06151FA8BDD" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_E282D759CEE81E1DD5EAF06151FA90D1" xlink:type="locator" />
    <definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_E282D759CEE81E1DD5EAF06151FA90D1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_11E99BD9A848B52CD631F06151FA0F29" xlink:type="locator" />
    <definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_11E99BD9A848B52CD631F06151FA0F29" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_75A8C0F0EC560B10C90CF06151FABD9F" xlink:type="locator" />
    <definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6904B48A7F5B5B4F937AF06151F99B37" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_75A8C0F0EC560B10C90CF06151FABD9F" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/StockBasedCompensationSummaryOfUnvestedStockOptionsDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/StockBasedCompensationTables" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/StockBasedCompensationValuationAssumptionsDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/StockholdersEquity" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/StockholdersEquityDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/SummaryOfSignificantAccountingPolicies" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/SummaryOfSignificantAccountingPoliciesConcentrationRiskDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ConcentrationRiskLineItems" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_CCC3783616F15A5BA24DBD21F1FF8203" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ConcentrationRiskTable" xlink:label="loc_us-gaap_ConcentrationRiskTable_F8D79A3863633B3F1AC4BD21F1FEF82B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_CCC3783616F15A5BA24DBD21F1FF8203" xlink:to="loc_us-gaap_ConcentrationRiskTable_F8D79A3863633B3F1AC4BD21F1FEF82B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_MajorCustomersAxis" xlink:label="loc_us-gaap_MajorCustomersAxis_D4B0503C0B393B2E23C9BD21F1FEB4C2" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_F8D79A3863633B3F1AC4BD21F1FEF82B" xlink:to="loc_us-gaap_MajorCustomersAxis_D4B0503C0B393B2E23C9BD21F1FEB4C2" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="loc_us-gaap_NameOfMajorCustomerDomain_042C2467E4589980FEC5BD21F1FEC80D_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MajorCustomersAxis_D4B0503C0B393B2E23C9BD21F1FEB4C2" xlink:to="loc_us-gaap_NameOfMajorCustomerDomain_042C2467E4589980FEC5BD21F1FEC80D_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NameOfMajorCustomerDomain" xlink:label="loc_us-gaap_NameOfMajorCustomerDomain_042C2467E4589980FEC5BD21F1FEC80D" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MajorCustomersAxis_D4B0503C0B393B2E23C9BD21F1FEB4C2" xlink:to="loc_us-gaap_NameOfMajorCustomerDomain_042C2467E4589980FEC5BD21F1FEC80D" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_EogResourcesIncMember" xlink:label="loc_ngs_EogResourcesIncMember_0F078C467A4B5DFC1FF8BD21F1FEE8AA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_042C2467E4589980FEC5BD21F1FEC80D" xlink:to="loc_ngs_EogResourcesIncMember_0F078C467A4B5DFC1FF8BD21F1FEE8AA" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_PromatconMember" xlink:label="loc_ngs_PromatconMember_13F74138714F4B513143BD21F1FE7393" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_042C2467E4589980FEC5BD21F1FEC80D" xlink:to="loc_ngs_PromatconMember_13F74138714F4B513143BD21F1FE7393" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_OxyMember" xlink:label="loc_ngs_OxyMember_6782BBB495F5B915A415BD21F1FE90AA" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_042C2467E4589980FEC5BD21F1FEC80D" xlink:to="loc_ngs_OxyMember_6782BBB495F5B915A415BD21F1FE90AA" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_DevonEnergyProductionIncMember" xlink:label="loc_ngs_DevonEnergyProductionIncMember_8E041EBB27E0738C5B7ABD21F1FEA391" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NameOfMajorCustomerDomain_042C2467E4589980FEC5BD21F1FEC80D" xlink:to="loc_ngs_DevonEnergyProductionIncMember_8E041EBB27E0738C5B7ABD21F1FEA391" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_5CCB6FA60C1476E6B651BD21F1FEAC94" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_F8D79A3863633B3F1AC4BD21F1FEF82B" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_5CCB6FA60C1476E6B651BD21F1FEAC94" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_D9776EF168EED963795CBD21F1FE5883_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_5CCB6FA60C1476E6B651BD21F1FEAC94" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_D9776EF168EED963795CBD21F1FE5883_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_D9776EF168EED963795CBD21F1FE5883" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_5CCB6FA60C1476E6B651BD21F1FEAC94" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_D9776EF168EED963795CBD21F1FE5883" xlink:type="arc" />
    <loc xlink:href="ngs-20141231.xsd#ngs_SalesRevenueGoodsNetAndRentalIncomeMember" xlink:label="loc_ngs_SalesRevenueGoodsNetAndRentalIncomeMember_08125028E35EA1691CCEBD21F1FEAACA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_D9776EF168EED963795CBD21F1FE5883" xlink:to="loc_ngs_SalesRevenueGoodsNetAndRentalIncomeMember_08125028E35EA1691CCEBD21F1FEAACA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccountsReceivableMember" xlink:label="loc_us-gaap_AccountsReceivableMember_E487ECB4EBFD3DEC430FBD21F1FFEF5C" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_D9776EF168EED963795CBD21F1FE5883" xlink:to="loc_us-gaap_AccountsReceivableMember_E487ECB4EBFD3DEC430FBD21F1FFEF5C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_DEEBE2A3DF385F521E2FBD21F1FF8BB1" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_F8D79A3863633B3F1AC4BD21F1FEF82B" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_DEEBE2A3DF385F521E2FBD21F1FF8BB1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_EFABCE589B9A32811864BD21F1FFBE2B_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_DEEBE2A3DF385F521E2FBD21F1FF8BB1" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_EFABCE589B9A32811864BD21F1FFBE2B_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_EFABCE589B9A32811864BD21F1FFBE2B" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_DEEBE2A3DF385F521E2FBD21F1FF8BB1" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_EFABCE589B9A32811864BD21F1FFBE2B" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_90503E0132FAD4878401BD21F1FFC456" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_EFABCE589B9A32811864BD21F1FFBE2B" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_90503E0132FAD4878401BD21F1FFC456" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_A3F668B9F2832A90499DBD21F1FF22DB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_CCC3783616F15A5BA24DBD21F1FF8203" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_A3F668B9F2832A90499DBD21F1FF22DB" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/SummaryOfSignificantAccountingPoliciesIntangiblesDetails" xlink:type="extended">
    <loc xlink:href="ngs-20141231.xsd#ngs_IntangibleAssetsLineItems" xlink:label="loc_ngs_IntangibleAssetsLineItems_B0141A0B20A49331453004436149B4DC" xlink:type="locator" />
    <loc xlink:href="ngs-20141231.xsd#ngs_IntangibleAssetsTable" xlink:label="loc_ngs_IntangibleAssetsTable_8CC6CF9FCEC49DCEBCC40443614803BA" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ngs_IntangibleAssetsLineItems_B0141A0B20A49331453004436149B4DC" xlink:to="loc_ngs_IntangibleAssetsTable_8CC6CF9FCEC49DCEBCC40443614803BA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_EA4252B504807D7387D504436148C5FE" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ngs_IntangibleAssetsTable_8CC6CF9FCEC49DCEBCC40443614803BA" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_EA4252B504807D7387D504436148C5FE" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3D07656BB11639A7C9C0044361484D80_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_EA4252B504807D7387D504436148C5FE" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3D07656BB11639A7C9C0044361484D80_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3D07656BB11639A7C9C0044361484D80" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_EA4252B504807D7387D504436148C5FE" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3D07656BB11639A7C9C0044361484D80" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DevelopedTechnologyRightsMember" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_A6556A060DAD7D09E02104436148AE43" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3D07656BB11639A7C9C0044361484D80" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_A6556A060DAD7D09E02104436148AE43" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_TradeNamesMember" xlink:label="loc_us-gaap_TradeNamesMember_58067D9AAA14E081245A044361482697" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3D07656BB11639A7C9C0044361484D80" xlink:to="loc_us-gaap_TradeNamesMember_58067D9AAA14E081245A044361482697" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_488FD4D7EB644344CB1A044361480840" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ngs_IntangibleAssetsTable_8CC6CF9FCEC49DCEBCC40443614803BA" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_488FD4D7EB644344CB1A044361480840" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_97A541213BD35DD09B1104436148254F_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_488FD4D7EB644344CB1A044361480840" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_97A541213BD35DD09B1104436148254F_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_97A541213BD35DD09B1104436148254F" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_488FD4D7EB644344CB1A044361480840" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_97A541213BD35DD09B1104436148254F" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_TradeNamesMember" xlink:label="loc_us-gaap_TradeNamesMember_BBB3575C65FAEB030653044361495F24" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_97A541213BD35DD09B1104436148254F" xlink:to="loc_us-gaap_TradeNamesMember_BBB3575C65FAEB030653044361495F24" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_19B65F69E25067FA074E044361491870" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_IntangibleAssetsLineItems_B0141A0B20A49331453004436149B4DC" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_19B65F69E25067FA074E044361491870" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_91D751484A7720E22A87044361491936" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_IntangibleAssetsLineItems_B0141A0B20A49331453004436149B4DC" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_91D751484A7720E22A87044361491936" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_CE1D265C18E6B30BD359044361491C68" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_IntangibleAssetsLineItems_B0141A0B20A49331453004436149B4DC" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_CE1D265C18E6B30BD359044361491C68" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7F23F527E447E0D83FB604436149A082" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_IntangibleAssetsLineItems_B0141A0B20A49331453004436149B4DC" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7F23F527E447E0D83FB604436149A082" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_CA6FFB83F84484D6183A04436149FD86" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7F23F527E447E0D83FB604436149A082" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_CA6FFB83F84484D6183A04436149FD86" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_B70BD9CECA7B90CE6CEE04436149ACDA" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7F23F527E447E0D83FB604436149A082" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_B70BD9CECA7B90CE6CEE04436149ACDA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_F3CE9AB8CCA248C37BB3044361499447" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7F23F527E447E0D83FB604436149A082" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_F3CE9AB8CCA248C37BB3044361499447" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_3628A84A0AD96419A67E04436149DCAA" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7F23F527E447E0D83FB604436149A082" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_3628A84A0AD96419A67E04436149DCAA" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_B02AE9588D6FB8B00F2104436149E04C" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7F23F527E447E0D83FB604436149A082" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_B02AE9588D6FB8B00F2104436149E04C" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_21CAE4CA7E86A855FD6304436149BE37" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract_7F23F527E447E0D83FB604436149A082" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_21CAE4CA7E86A855FD6304436149BE37" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_D5479466AFDB6D399A2E044361495754" xlink:type="locator" />
    <definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_IntangibleAssetsLineItems_B0141A0B20A49331453004436149B4DC" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_D5479466AFDB6D399A2E044361495754" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNetAbstract" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_CFFDE5B951CAB15B0C770443614911F1" xlink:type="locator" />
    <definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_IntangibleAssetsLineItems_B0141A0B20A49331453004436149B4DC" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_CFFDE5B951CAB15B0C770443614911F1" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_1E8B09D587EA29CECAA204436149E493" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_CFFDE5B951CAB15B0C770443614911F1" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_1E8B09D587EA29CECAA204436149E493" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_756F9FF490214F1F742F04436149E1B6" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_CFFDE5B951CAB15B0C770443614911F1" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_756F9FF490214F1F742F04436149E1B6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_8B8B753B6B119D927772044361496437" xlink:type="locator" />
    <definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_CFFDE5B951CAB15B0C770443614911F1" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_8B8B753B6B119D927772044361496437" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_F8E0B7E50A1B6E42D3460443614904C7" xlink:type="locator" />
    <definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsNetAbstract_CFFDE5B951CAB15B0C770443614911F1" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_F8E0B7E50A1B6E42D3460443614904C7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill_EEEE95B62855AFABF5B10443614AB03F" xlink:type="locator" />
    <definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ngs_IntangibleAssetsLineItems_B0141A0B20A49331453004436149B4DC" xlink:to="loc_us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill_EEEE95B62855AFABF5B10443614AB03F" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/SummaryOfSignificantAccountingPoliciesNarrativeDetails" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:type="extended" />
  <definitionLink xlink:role="http://naturalgaservices.com/role/SummaryOfSignificantAccountingPoliciesPropertyAndEquipmentDetails" xlink:type="extended">
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_CA6F2DBF542B20A1761BBD21F22F5787" xlink:type="locator" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_40189A9324671450A65BBD21F22E672A" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_CA6F2DBF542B20A1761BBD21F22F5787" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_40189A9324671450A65BBD21F22E672A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_MajorPropertyClassAxis" xlink:label="loc_us-gaap_MajorPropertyClassAxis_E1623EE3C8BF60496090BD21F22EC31E" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_40189A9324671450A65BBD21F22E672A" xlink:to="loc_us-gaap_MajorPropertyClassAxis_E1623EE3C8BF60496090BD21F22EC31E" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_MajorPropertyClassDomain" xlink:label="loc_us-gaap_MajorPropertyClassDomain_A882D3AB724738F38979BD21F22E28D7_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MajorPropertyClassAxis_E1623EE3C8BF60496090BD21F22EC31E" xlink:to="loc_us-gaap_MajorPropertyClassDomain_A882D3AB724738F38979BD21F22E28D7_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_MajorPropertyClassDomain" xlink:label="loc_us-gaap_MajorPropertyClassDomain_A882D3AB724738F38979BD21F22E28D7" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MajorPropertyClassAxis_E1623EE3C8BF60496090BD21F22EC31E" xlink:to="loc_us-gaap_MajorPropertyClassDomain_A882D3AB724738F38979BD21F22E28D7" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EquipmentLeasedToOtherPartyMember" xlink:label="loc_us-gaap_EquipmentLeasedToOtherPartyMember_8ED00CE4DE0E541E219DBD21F22EBE08" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorPropertyClassDomain_A882D3AB724738F38979BD21F22E28D7" xlink:to="loc_us-gaap_EquipmentLeasedToOtherPartyMember_8ED00CE4DE0E541E219DBD21F22EBE08" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_1AE3B916378031D170DCBD21F22FF7A5" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_40189A9324671450A65BBD21F22E672A" xlink:to="loc_us-gaap_RangeAxis_1AE3B916378031D170DCBD21F22FF7A5" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_3FCEC292C181FCAE4016BD21F22F99A6_default" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_1AE3B916378031D170DCBD21F22FF7A5" xlink:to="loc_us-gaap_RangeMember_3FCEC292C181FCAE4016BD21F22F99A6_default" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_3FCEC292C181FCAE4016BD21F22F99A6" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_1AE3B916378031D170DCBD21F22FF7A5" xlink:to="loc_us-gaap_RangeMember_3FCEC292C181FCAE4016BD21F22F99A6" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_DA6A7446A741958DC68ABD21F22F98BB" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_3FCEC292C181FCAE4016BD21F22F99A6" xlink:to="loc_us-gaap_MinimumMember_DA6A7446A741958DC68ABD21F22F98BB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_07E4A5B0341536396D46BD21F22F76FB" xlink:type="locator" />
    <definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_3FCEC292C181FCAE4016BD21F22F99A6" xlink:to="loc_us-gaap_MaximumMember_07E4A5B0341536396D46BD21F22F76FB" xlink:type="arc" />
    <loc xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_3887F2FA421AFC77E819BD21F22FDA96" xlink:type="locator" />
    <definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_CA6F2DBF542B20A1761BBD21F22F5787" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_3887F2FA421AFC77E819BD21F22FDA96" xlink:type="arc" />
  </definitionLink>
  <definitionLink xlink:role="http://naturalgaservices.com/role/SummaryOfSignificantAccountingPoliciesTables" xlink:type="extended" />
</linkbase>
