In the construction of modern buildings, the presence of openings became a necessity nowadays in order to accommodate the many pipes and ducts required for different services. On the other hand, the presence of these openings in RC beams affects their structural behavior. One important behavior that needs further study would be torsion .Currently, there are no guide lines available to analyze or design RC beams with web openings under pure torsion. Thus, the main objective of this research is to investigate the behavior of simply supported RC beams with openings subjected to pure torsion. The experimental study is conducted on ninth beams subjected to pure torsion loading in order to investigate the optimum opening shape; circular, square, and rectangular as well as study the effect of using varying opening length with same height. Systematic measurements such as the cracking torque, the ultimate torque, the angle of rotation of the beam at cracking and the ultimate load are conducted for further understanding the beam behavior under torsion. Finally, the experimental results showed that using circular or square opening with same area is the better than using rectangular opening.