Authors report 42 cases of humeral shaft fractures, which were treated with plate fixation in 19 cases and intramedullary(IM) nailing in 23 cases, from January 1992 to December 1996. The average time of operation in plate fixation was 100 minutes and that in Im nailing was 65 minutes. The nonunion in plate fixation was 2(10.5%)cases and that in IM nailing was 4(17.4%)cases. Other complications of plate fixation were 2 cases of wound infection and 2 cases of radial nerve palsy. Those of IM nailing were 1 case of limited motion of the shoulder and 1 case of wound infection. After reviewing above reslts, we concluded that there were no marked difference between the two operative method in bone union of humeral shaft fracture cxcept diversity of complication.