In the treatment of an unstable fracture of the distal radius, the anatomical reduction of articular surface and the maintenance of radial length are essential. Recently, more extensive therapeutic method was introdced for reduction and maintenance of distal radius fracture. To compare the results between type C2 and C3 that were treated with pinning and the results between pinning and pinning with external fixation in type C3 according to AO classification, we analysed anatomical and functional results of unstable fracture of the distal radius from June, 1994 to september, 1996 at DanKook University Hospital. There were 12 cases of C2 type with pinning, 17 cases of C3 type with pinning and 14 cases C3 type with external fixation and pinning. Among the 43 cases, the most commom type was C3 (31cases), and open fractures were 6 (14%)cases. The following results were obtained; 1. For comparison of C2 type with C3 type that were treated with pinning, the results of C2 type were better anatomically and functionally. 2. For comparison of percutaneous pinning with percutaneous pinning and external fixation in C3 type, the results of C3 type that were treated by pinning and external fixation were better anatomically and functionally.