The present paper shows and discusses some of the results obtained within an experimental investigation carried out on ten RC beams strengthened in shear by externally bonded FRP sheets. The aim of the study is to analyze the influence that the geometrical percentage of transverse steel reinforcement could have on the FRP resisting action. In particular, the objectives of the experimental campaign have been to explore the possible interaction between FRP and steel transverse reinforcement resisting actions, analysing the deformation behaviour of the shear resisting system (FRP, transverse steel, concrete) and the modes of failure of the strengthened beams.