According to literatures, the different types of fractures can occur as a result of arm wrestling ; Spiral fracture of the humeral shaft associating often with a bntterfly fragment, fracture of medial epicondyle of the humerus, and the marginal radial head fracture with anterior dislocation. The last type is very rarely reported. In addition to the fracture occurrence, other injuries such as muscular strain of the arm, and sprain or luxation of the shoulder, elbow and wrist joints can be taken place. However, it is thought that the most of those injuries by arm wrestling have been treated simply by general practioners unreported. The arouse the attention of the jury of the game, wrestlers and the surgenons, the cases of bony injuries sustained during the arm-wrestling are reported. Thirteen patients were treated by us since 1977. Among them, five cases had fractures of the humeral shaft, and eight cases had fractures of medial epicondyle of the humerus. Among the five shaft fractures, three were treated by conservatively, and two by operatively. Among 8 avulsion fractures of the medial epicondyle only two were treated conservatively, and 6 operatively. One patient sustained the medial epicondylar avulsion fracture twice for which K-wire fixation treatment was done. The results of treatment were all satisfactory. However, because of the possibility of wrestlers sustaining such injuries. Arm wrestling should not be considered a totally benign sport.