PURPOSE: The purpose of this study is to analyze the clinical and radiological result of surgical treatment for femoral shaft nonunion. MATERIALS AND METHODS: From January 1993 to December 1999, 21 cases of femoral shaft nonunion were treated surgically and followed for an average of 15 months. We analyzed initial cause of injuries, classification of fractures, and cause of nonunion in clinically and radiologically. The authors analyzed the average time to union and results after surgical treatment by rigid internal fixation with interlocking intramedullary nail and autogenous bone graft. RESULTS: The mean duration of bony union was 22 weeks and bony union achieved in 18 cases(85.7%) of 21 cases. The complications were shortening of leg length and limping gait in 2 cases, partial limitation of knee joint in 2 cases, superficial infection in 2 cases. CONCLUSION: Rigid internal fixation with interlocking intrameduallary nail and bone graft is useful method of treatment for femoral shaft nonunion according to cause and type of nonunion.