In　this　paper　a　detailed　parametric　study　of　loss　factor　of　laminated　composite　beams　with　embedded　viscoelastic　layers　has　been　performed　using　the　finite-element-based　modal　strain　energy　method　revised　to　deal　with　the　frequency　dependency　of　viscoelastic　materials.　The　contribution　of　energy　dissipation　due　to　fiber-reinforced　composites　is　also　taken　into　account　for　a　more　accurate　prediction　of　loss　factor.　The　effects　of　different　parameters　such　as　ply　orientations,　location　of　damping　layers　and　thickness　of　the　laminates　on　the　modal　loss　factor　are　investigated　for　both　single　damping　layer　and　double　damping　layer　composite　beams.　©　2006　Inderscience　Enterprises　Ltd.