The strengthening of RC beams with CFRP laminates has been extensively studied, and design recommendations have been published in many countries (ACI 440, CNR-DT200, CEB-FIP 01, etc.). Few data are available for Near Surface Mounted (NSM) FRP strengthening techniques or for concrete beams that are repaired first using cementitious mortars and then reinforced with FRP materials. A specific experimental campaign, with more than 200 beams, has been carried out to investigate many factors that can affect design in the common practice, such as concrete compressive strength, concrete fracture energy, FRP reinforcement ratio, FRP type, repair technique (plating, NSM, new concrete cover), fatigue, and aggressive environment. Tests on 4-point bending showed the good performance of FRP strengthening, as the minimum increment in peak bending load was 110 percent, and the maximum was 430 percent. The influence of fatigue, if the peak cyclic load is kept below 30 percent of ultimate quasi-static load, is negligible in the overall performance. Saltwater contact and temperature variation have a more significant effect in reducing ultimate capacity, especially because the internal steel reinforcement corrodes, and the interface adhesion strength degrades. The effect of concrete cover replacement was also investigated-the influence of high strength shrinkage-compensated cementitious mortar is negligible because the interface adhesion with the original concrete is similar to the epoxy-concrete adhesion. Moreover, the internal steel reinforcement is protected against aggressive environments.