In order to know if peripheral neoropathies in the upper extremities of paraplegic individuals are induced by participating in wheelchair marathon races, we performed nerve conduction studies bilaterally on the median, ulnar, and radial nerves of 10 male wheelchair marathon racers, and on 10 male sedentary paraplegic individuals. In five of 10 paraplegic racers, and in nine of 10 sedentary paraplegics there was a decrease of motor nerve conduction velocities and/or prolongation of motor or sensory nerve distal latencies. Abnormal results in all of the nerve conduction studies were 3.2% and 13.6% in paraplegic racers and sedentary paraplegics, respectively. Although paraplegic racers had fewer peripheral neuropathies in the upper extremities than did sedentary paraplegics, ulnar lesions due to involvement of the deep motor branch and at the elbow were a characteristic feature of nerve injuries, presumably caused by wheelchair marathon racing. It is suggested that although a wheelchair marathon is generally a safe sport, wearing gloves and handling a wheelchair in the correct way during the race are necessary to prevent nerve injuries.