PURPOSE: To review the clinical and radiographic results of the treatment of unstable intertrochanteric femoral fractures with a proximal femoral nail (PFN). MATERIALS AND METHODS: We reviewed 47 unstable intertrochanteric femoral fracture cases that had been treated with a PFN operatively. The clinical and radiographic results and complications were analyzed. The mean age was 76.8 years old (62~96 years old) and the mean duration of follow-up was 15 months (12~24 months). RESULTS: The postoperative walking ability was regarded as satisfactory when the patient could walk alone using an walking frame without others aids and satisfactory results was achieved in 43 cases (91.5%). In all cases the radiologic bone union was obtained. The average sliding of femoral neck screw was 3.0 mm and the average change of neck-shaft angle was 2.6 degree. There were three cases of postoperative complication which were including 1 case of cut-out of femoral neck screw, local superficial infection in 1 case and pain complaints over trochanteric area in 1 case. CONCLUSION: The PFN is an useful implant for the treatment of unstable intertrochanteric femoral fracture because of the simplicity of the surgical technique and the low level of the complications encountered.