From January 1991 to August 1996, we experienced 17 cases of metal failure among 150 cases of plate fixation of femur fracture. We analyzed the cases and obtained the following results: 1. Among 17 cases, 15 cases were closed fracture and 2 cases were open fracture. In 11 cases, the fractures were located on the midshaft of femur and most of them was segmental or comminuted. According to AO classification, 14 cases(82%) were type B(B1:1, B2:4) and C(C1:7, C3:2). 2. The interval between initial operation and metal failure was 8 months on average. 3. The cause of metal failure were bone defect remaining after initial operation, fragment necrosis due to periosteal denuding of large free bone fragments, early weight bearing, selection of inappropriate implants and improper operation technique. 4. Plate breakages were occured in 11 cases and screw fractures and screw loosening in 6 cases. Most of plate breakage was due to remaining bone defects, and most of screw fractures and loosening was due to inappropriate implants and improper operation techinque. In conclusion, accurate preoperative evaluation on the fracture site, fracture pattern and appropriate selection of internal fixative are important for proper bone healing. Based upon our result, we suggest semiopen technique with minimal soft tissue injury and initial early bone graft for bone defect.