The simultaneous ipsilateral fractures of the arm and forearm are relatively rare and there is no exact method of treatment for these fractures. Authors has clinically analized 37 cases of these fractures which are treated between September, 1973 and May, 1987 at the Department of Orthopedic Surgery, Hanyang University College of Medicine. The results can be summarized as follows. l. Among 440 patients with humeral fracture, there were associated fractures of the ipsilateral forearm bone in 69 patients (13. 4%). 2. The main cause of these fracture was traffic accident and the next one was fell from a height. 3. The most frequently associated injury was nerve paralysis. 4. The methods of treatment were classified as follows . 1 st method Both arm and forearm were treated by internal fixation (32.1%). 2nd method The arm was treated by internal fixation and the forearm by conservative method (11.8%). 3rd method The arm was treated by conservative method and the forearm by in- ternal fixation (11.8%). 4rdmethod Both arm and forearm were treated by conservative method (44. 3%). 5. By Andersons criteria, excellent and satisfactory results were obtained in 47. 1% of cases which were treated by mainly 1 st method.