Diaphyseal fractures of the radius and ulna present high incidence of malunion and nonunion because of difficulty in reduction and maintenence of two mobile, parallel ones in the presence of the pronating and supinating muscles which exert angulatory as well as well as rotational forces. The author divided the traceable patients into two groups, the one was the group treated with AO compression plates and the other one was the roup treated with Rush pin in radius and AO compression plate in ulna, and compared the results in the aspect of healing time and functional results. The results were as follows; 1.Those two groups were demographically similar. 2.The immobilization period and the radiologic bone union time did not differentiate two groups significantly. 3.In plate group, one nonunion, one nerve injury and two superficial wound infection were occurred. 4.Between the two operative methods selected alternatively, immobilization period, radiologic bone union and fuctional results were not different significantly, but the Rush pinning method was preferred due to simple operation technique, small operation scar, short operation time, a little blood loss, a few complication.