Treatment of femur fracture by closed flexible intramedullary nailing is known to have many advantages, such as low infection rate, early ambulation, and minimal physiologic stress protection effect. The fracture healing with external bridging callus is seldom disturbed and sufficient periosteal callus formation used to be observed due to preserved fracture hematoma in this type of treatment. On the other hand, it has disadvantages as well. It can’t be done without image intensifier and fracture table. Unstable fractures with large unicortical butterfly fragment and bicortical fractures tend to redisplace even after good fixation with this technique. We have treated 19 femur fractures out of 18 patients with closed flexible intramedullary nailing and the following results were obtained: l. Among 18 patients, 15 were male and 3 were female, and their average age was 35 years. 2. Of the 19 cases, 15 were in shaft and 4 were in intertrochanteric level of femur. The shaft cases, 15 in number were distributed as 3 in proximal, 10 in middle and 2 in distal level. 3. According to the extent of comminution, no-communition cases were 2, unicortical-small fragment cases were 9, unicortical-large fragment cases were 2 and segmental fractures were 2 in number. 4. Average healing time was 12.2 weeks which seems a little bit shorter than open intramedullary nailing or compression plate fixation, and periosteal callus formation was found predominant in healing process. 5. Functional assessment was made of the femur shaft fractures according to Denker’s classification, and excellent or good results were 86.7% of the total and satisfactory result was 13.3%. 6. Complications which we experienced were vertical cortical splitting(3 cases), migration of nail(2 cases) and displacement of fracture(2 cases).