Treatment of the femoral shaft fractures in adolescents with open physis is somewhat controversial. Historically, these fractures have been treated with nonoperative methods, but adolescents are less tolerant to the prolonged immobilization than younger children. Futhermore, conservative treatment in this age group may be prone to result in more complicati.ons such as malunion and shortening than that in the younger age group. Therefore many authars prefer the aperative method for femoral shaft fractures in the adolescents. The authors reviewed 22 cases of adolescent femoral shaft fractures treated during the period from January, 1988 to June 1992. Seven cases were treated conseratively, eleven by open reduction and intenal fixation with DCP, and four by closed intramedullary nailing. The patients treated with traction and casting showed more often complications such as angular deformity and bone shortening than in the operative methods. In comparing with those cases of plating, the patients of intramedullary nailing had statistically signiticant shorter ansthesic time and less blood loss in operation. All of the fractures treated with the intramedullary nails healed without malunion or leg length discrepancy, and there was no evidence of growth plate arrest. Results of this study suggest that closed intramedullary nailing of femur fractures in aldolescents is an effective treatment aption.