This paper presents the results of an experimental study of the flexural behavior of corroded RC beams. The corrosion level was 10% and 15% as a mass loss of the reinforcing bars. Three specimens were conducted as a control: the first one was un-corroded beam and two were corroded with the aforementioned corrosion levels. The rest were retrofitted using different techniques: replacement of the deteriorated concrete at the tension side with a high-performance cementitious mortar layer, adding high-performance mortar at the compression zone, using external prestressing reinforcement at the tension zone, and a combination of them. The stress in the prestressing tendons was kept at a value of 0.25fpy and 0.38fpy. The results revealed that, the specimens retrofitted by a combination of an external prestressing bars and using highperformance cementitious layer at the tension zone showed a significant increase in capacity about 34% compared with the 10% mass loss corroded control specimens.