Various methods of internal fixation have been used for the treatment of femoral fractures. In 1970, Ender and Simon-Weidner described their method of flexible intramedullary nailing for the treatment interterochanteric and subtrochteric fractures. This method was widely used and obtained good result but Pankovich described that the intertrochsnteric fraeture, particullary unstable, is the worst indication due to many complications and difficulties in the procedure, We used flexible intramedullary nailing fot 115 cases of the femoral fractures from Jan. 1985 to Mar, 1988 at the Department of Orthopedir Surgery, Soonchunhyang University Hopsital with following results. 1. The intertrochanteric, subtrochanteric and shaft fractures were healed within 12.6 weeks, 15.8 weeks and 17.3 weeks respectively, however, unstable or comminuted fractures took more time to be healed. 2. The most frequent complication was shortening (20 cases), flollowed by nail migration, broken nail, delayed and non-union in orders. 3. Nonunion and delayed union were frequently occured at the distal shaft fractures and developed broken nail. the healing time is longer than those of other sites, So, the flexible intramedullary nailing on the distal shaft fractures of femur may be inappropriate. 4. In 8 cases of unstable or comminuted fractures of subtrochanteric and shaft, open reduction and cerclage wiring were done before nail insertion. We could prevent shortening and start early weight bearing and obtain the good result of bone union. 5. In 8 cases of locking with screw through the nail eyes, there was no nail migration and knee joint pain was almost none. 6. Among 4 cases of secondary Ender nailing and bone graft, one case was infected and the others were united after 11.7 weeks. In nonunion, this method may be useful. 7. Varization and shortening were developed in the unstable intertrochanteric fractures but clinically they were not significant. We recommed ender nailing for the unstable intertrochanteric fractures for experienced surgeons.