Five　beams　were　tested　up　to　failure　to　study　the　shear　behavior　of　concrete　beams　prestressed　with　fiber　reinforced　polymer　(FRP).　Different　factors　were　taken　into　consideration:　the　type　of　prestressing　tendons　and　the　shear　span　ratio.　The　shear　failure　modes　and　the　influence　of　different　factors　on　shear　behavior　were　investigated　in　details.　The　test　results　showed　that　FRP　prestressed　beams　without　stirrups　had　two　shear　failure　modes:　diagonal　compression　failure　and　shear　compression　failure;　the　shear　span　ratio　was　the　most　important　factor　to　determine　the　failure　mode　and　shear　capacity　of　the　prestressed　beams.　The　shear　capacity　of　concrete　members　prestressed　with　FRP　tendons　was　lower　than　that　of　concrete　beams　prestressed　with　steel　cables.　©　(2011)　Trans　Tech　Publications,　Switzerland.