The　interfacial　stresses　in　fiber　reinforced　plastic　(FRP)-reinforced　concrete　(RC)　hybrid　beams　were　studied　by　the　finite　element　method.　The　mesh　sensitivity　test　shows　that　the　finite　element　results　for　interfacial　stresses　are　not　sensitive　to　the　finite　element　mesh.　The　finite　element　analysis　then　is　used　to　calculate　the　interfacial　stress　distribution　and　evaluate　the　effect　of　the　structural　parameters　on　the　interfacial　behavior.　It　is　shown　that　both　the　normal　and　shear　stresses　at　the　interface　are　influenced　by　the　material　and　geometry　parameters　of　the　composite　beam.　This　research　is　helpful　for　the　understanding　on　mechanical　behavior　of　the　interface　and　design　of　the　FRP-RC　hybrid　structures.　(C)　2003　Elsevier　Ltd.　All　rights　reserved.