Shape memory alloys (SMAs) have a special characteristic which is called shape memory effect (SME). SME means that the material returns to its initial shape after having been deformed. If the returning to the initial shape is prevented by a mechanical fixation, stress develops in the SMA. In the form of ribbed bars/strips, the SMAs can therefore be used as reinforcement in new reinforced concrete (RC) structures but also for strengthening of existing RC structures. A novel iron-based shape memory alloy (Fe-SMA) has been developed and patented at Empa in Switzerland. This Fe-SMA shows high tensile strength, excellent shape recovery stress (i.e. prestress), high elastic stiffness, low material costs and simple manufacturing process in comparison to nickel-titanium (NiTi) based alloys. This Fe-SMA has therefore a huge potential for structural applications. In this paper, an investigation on the flexural behavior of strengthened beams with Fe-SMA bars/strips is presented. Ribbed Fe-SMA bars and strips were used for strengthening and prestressing of real scale RC beams. The experimental results on beams strengthened with near surface mounted (NSM) Fe-SMA ribbed strips, beams strengthened with Fe-SMA bars embedded in a additionally applied shotcrete layer, and one beam without any strengthening (reference beam) are presented. These two different strengthening techniques, NSM and shotcreting, are compared and the potential applications are stated. The activation (i.e. prestressing) procedure of Fe-SMA bars/strips and the behaviors of the strengthened beams are explained in details. The behavior of the beams at the serviceability stage was significantly improved by the prestressed Fe-SMA bars/strips. The results show that the application of ribbed Fe-SMA bars/strips to strengthen RC structures was successful.