OBJECTIVE To investigate the cardiorespiratory endurance of the physical fitness of amputees and able-bodied subjects of the same ages and to demonstrate deterioration of the physical fitness of the amputees. METHODS The test subjects were 31 amputees. Eighteen able-bodied persons served as controls. The incremental exercise test was performed to evaluate physical fitness. Sixteen of 31 amputees underwent endurance training by using a cycle ergometer driven by the intact leg, and their physical fitness was evaluated after completion of the endurance training program. RESULTS The Vo2max, anaerobic threshold, and maximum workload for the amputees were significantly lower than those of the able-bodied group. The equivalent values for the endurance training group before exercise treatment were 18.0, 12.1, and 63.9, respectively. After exercise treatment, these values significantly increased, and there was no significant difference from the able-bodied subjects. CONCLUSIONS This study showed that the physical fitness of amputees was clearly lower than that of the able-bodied subjects and that the amputees were able to recover from a poorly conditioned status after endurance training.