Abstract— This paper aims to study the use of externally bonded fiber reinforced polymers (EB-FRP) to strengthen beams with large web opening subjected to pure torsion. An experimental work has been carried out to investigate the torsional behavior up to failure of nine reinforced concrete beams having the same dimensions and reinforcement. One of them is solid without opening as a reference beam and one of the remaining eight beams was tested without anystrengthening and seven beams were strengthened with carbon fiber reinforced polymer (CFRP) with different schemes. The major parameter included in this study is the strengthening effect of different schemes of CFRP sheets on the behavior of RC beams with large web opening under pure torsion. The experimental results showed that the beam strengthened with a complete 90°, to the beam axis, wrapping around the chords and the solid parts near the opening region gives the best results and its torsional strength is close to the torsional strength of the reference solid beam. Also results have been compared with the design approaches of some international codes and analytical procedure produced by previous researchers. Finally, a simple proposed equation is produced to estimate the torsional moment capacity of a strengthened reinforced concrete beam with opening. The proposed equation confirms the accuracy and effectiveness of the experimental result.