An experimental study was performed on five reinforced concrete (RC) columns to investigate the structural behavior of highly corroded RC columns. Four of the RC columns were corroded using an accelerated corrosion method for different corrosion levels at longitudinal bars as 15.4, 20.2, 27.3 and 28.3%. RC columns were tested under cyclic load for a constant axial load ratio of 0.40. After the loading test, the actual corrosion levels were obtained by extracting the longitudinal bars and stirrups following the breaking of the RC columns. Load-displacement curves, ductility ratios and energy absorption capacities of tested RC columns were obtained. Test results revealed that the ductility ratios of corroded RC columns should be determined in accordance with energy-based or bilateral failure criteria due to the misleading of increased ductility ratios of corroded RC columns based on the displacement method.