There are many difficult problems and various methods in the treatment of difficult fractures of the femur. Form May 1991 to August 1994, 9 cases of difficult fractures of the femur were treated with Ilizarov external fixator. We obtained good result for all cases as follow : 1. There were 1 case of severely segmental and comminuted fracture with bone loss, 3 cases of infected nonunion after internal fixation(2 cases combined with bone loss), 2 cases of non-union after internal fixation and 3 cases of severely segmental and comminuted fractures. The traffic accident injury was in 6 cases and the falling down injury was in 3 cases. 2. The bone union was obtained in all cases and the duration of Ilizarov external fixator application was minimum 7.7 months up to 19 months with an average of 1.3 months and full weight bearing was possible in all cases after removal of the Ilizarov external fixator. 3. We experienced 9 complication; there were 6 cases of pin tract infection which were controlled by antibiotic injection at that site and there were three cases of limitation of motion of knee. So we conclude that the Ilizarov external fixation technique is one of the effective methods for the treatment of difficult fracture of the femur(ex. segmental, comminuted fracture, bone defect, osteomyelitis and nonunion) in spite of having experienced only few cases.