It is usually difficult to obtain an exact reduction of bony mallet finger involving more than one third of the articular surface by closed manipulation and extension splinting and needs the operative treatment to obtain an exact anatomical reduction. Operative treatment of a mallet finger is a difficult procedure, fraught with many potential problems, including intraoperative fragmentation of dorsal lip fracture, difficulty of exposure and anatomical reduction of the fragment, skin slough, and postoperative loss of fixation. The purpose of this study is to evaluate the fixation technique and to reduce intraoperative complications. We retrospectively reviewed 13 patients of bony mallet fingers, who were treated by tension wire fixation between January 1994 and August 1995 at the Department of Orthopaedic Surgery, Kwangmyung Sung Ae Hospital. There were 6 male and 7 female pateints. The most common cause was sports injury (6 cases). According to Wehbe and Schneider classification, 8 cases were type II and subtype B, 7 cases were the other types. According to modified Abouna and Brown criteria, the clinical results were success in 10 cases and failure in 3 cases. Postoperative complications were superficial infeciton (2 cases), skin necrosis (1 case), nail deformity (1 case) and secondary extensor tendon rupture (1 case). In conclusion, tension wire fixation of bony mallet finger was a simple and effective fixation of the fragment under the direct vision, which make it possible to exercise early and fix sturdily. But it should be avoided some pitfalls associated with internal fixation of small bony fragments.