During an eight-year period, four tennis players, seven golfers, and nine baseball players were seen with a fracture of the hook of the hamate. Eighteen of these twenty patients were disabled by pain and after the fracture fragment was removed, all eighteen were relieved so that they returned to their athletic pursuits. Two patients were asymptomatic, their old fracture being discovered accidentally when they were treated for other injuries. Nineteen of the twenty patients had been examined before coming under our care, but the correct diagnosis had been made in only two. Conservative treatment, including rest, physical therapy, and injections of steroids into the wrist and hand, had not been beneficial. From the history and findings, we believe that these fractures were caused by a direct blow against the hook of the hamate caused by the handle of the tennis racket, golf club, or bat during a swing, and not by indirect force produced by the ligaments and muscles attached to the hook. The fracture was demonstrated in all twenty patients by a roentgenogram (profile view) of the carpal tunnel.