The　alternative　fuel　vehicles　(AFVs)　which　include　electric　vehicles　(EVs)　and　natural　gas　vehicles　(GVs)　have　gained　much　attention　in　recent　years　for　delivering　a　clean　and　low-carbon　urban　mobility.　The　AFV　development　is　promoting　the　coordination　among　electric　power,　natural　gas,　and　transportation　(ENT)　networks.　This　paper　proposes　a　coordinated　planning　method　for　investment　on　and　operation　of　emerging　urban　energy　infrastructures.　The　sites　and　sizes　of　refueling　stations　are　optimized　along　with　the　expansion　strategies　for　electric　power　distribution　network　(PDN)　and　natural　gas　distribution　network　(GDN).　First,　AFV　refueling　demands　are　analyzed　according　to　the　refueling　station　constraints　and　options,　and　transportation　network　(TN)　constraints.　Second,　the　coordinated　planning　model　for　PDN　and　GDN　is　formulated　along　with　respective　operation　constraints　in　PDN,　GDN,　and　TN.　An　efficient　MILP　solution　method　is　developed　for　the　proposed　optimization　problem.　Finally,　several　case　studies　verify　the　effectiveness　of　the　proposed　model　and　its　solution　method.　Compared　with　existing　solutions,　the　proposed　panning　method　offers　a　more　accurate　AFV　refueling　demand　model　with　various　refueling　options.　It　is　demonstrated　that　the　coordinated　planning　can　reduce　investment　and　operation　costs　of　urban　energy　infrastructures　by　exploring　the　pertinent　interactions　among　constrained　PDN,　GDN,　and　TN.　©　2010-2012　IEEE.