An experimental study was conducted to investigate the pure torsional moment capacities of corroded reinforced concrete beams. An accelerated corrosion pool was used to corrode the reinforcement bars embedded in reinforced concrete beams. Seven reinforced concrete beams at corrosion levels between 0% and 17% were examined under pure torsion tests. The actual corrosion levels were obtained by breaking the concrete and extracting the reinforcement bars from the concrete after the torsion tests. An empirical model was developed to predict the pure torsional moment capacities of the reinforced concrete beams as a function of the corrosion level. The experimental results showed that, compared to the cracking torque, the maximum torques and dissipated energy capacities of the corroded reinforced concrete beams were significantly reduced as the corrosion level increased. Nonuniform shear flow originating from the nonuniform formations due to corrosion through the depth of the diaphragm produced different cracking patterns. The failure modes of the corroded reinforced concrete beams were more severe if the diagonal compression struts were joined with bond cracking.