The purpose of this investigation was to analyze the causes of the metal failures, and to suggest reasonable methods that can prevent metallic failures in the treamtnet of femur shaft fractures. There were 27 metal failures in 25 patient who underwent internal fixation for the femur shaft fracture between May of 1990 and May of 1996. We analyzed the causes of injury, fracture site, associated injury and used implants for the femur shaft fractures. And also analyzed the interval since operation to metal failure, method of treatment, and complications following surgery for the metallic failures. There were 13 stainless steel DCP(dynamic compression plate), 4 titanium LC(low contact)-DCP, 7 interlocking IM(intramedullary) nails, 2 Kutscher nails, and I anatomical plate. The metal failure occurred on average 6.1 months after internal fixation. Eight stainless steel DCP, 4 LC-DCP and 1 anatomical plate failed at the empty hole located at the fracture site. With interlocking IM nail, 4 cases of failure occurred at the proximal 1/3 of femur and other 3 cases showed failure on distal interlocking hole in distal femoral shaft fractures. All failures developed at the fracture site in kuntscher nail. For the treatment of metal failures, we used stainless steel DCP in 12 cases, interlocking IM nail in 7 cases, Kuntcher nail in 2 cases, Ender nail in 1 case, dual plate in 1 case, and external fixation in 2 cases. Autogenous cancellous iliac bone graft applied in 20 cases for the augmentation of fracture site or to fill the defect area. There were 2 cases of re-failure, 2 chronic osteomyelitis, 1 fracture site infection, 2 delayed union and knee joint ankylosis in 1 case. Accurate preoperative evaluation of fracture site, fracture pattern and proper implant selection will be essential for the prevention of metal failures. Minimal soft tissue dissection, anatomical reduction and rigid internal fixation will be necessary for the satisfactory outcome in the treatment of femur shaft fractures. Augmentation with autogenous cancellous bone graft should be followed after internal fixation for the comminuted fractures or bony defect over the fracture site. Postoperative rehabilitation program should be individualized according to the preoperative fracture pattern, used implant, and fracture stability.