Retrofitting concrete structures with bonded fiber reinforced polymer (FRP) has grown to be a widely used method in all most parts of the world today. The main reason for the widespread application of FRP is that it is possible to obtain an effective strengthening with a relative small work effort. Furthermore, it is possible to carry out strengthening work without changing the current appearance or dimension of the structures. However, in most cases the bonded FRP materials are unstressed. If prestressing could be applied, better utilization of the strengthening material and a better strengthening result would most likely be achieved. Increasing research is carried out in the area of repair and upgrading of concrete structures with prestressed CFRP (Carbon Fiber Reinforced Polymers) materials. In this study, the flexural performance of reinforced concrete beams strengthened with CFRP plates using FRP bonding and prestressed FRP bonding has been mainly discussed by means of a Finite Element analysis.