Intramedullary nailing was performed on 520 femoral fractures in 500 patients. The series included eighty-six open fractures and 261 comminuted fractures. Closed intramedullary nailing was used in 497 femora and open intramedullary nailing with cerclage wiring, in twenty-three. The union rate was 99.1 per cent. The range of motion of the knee at follow-up averaged 130 degrees. Complications included four infections (0.9 per cent). Shortening of more than two centimeters occurred in ten patients (2.0 per cent) and malrotation of more than 20 degrees was observed in twelve patients (2.3 per cent). After prompt emergency measures had been taken, routine treatment included strong preoperative traction followed by accurate positioning of the patient on the operating table; selection of the correct insertion point for a properly sized, prebent, flexible, bullet-tipped nail; and accurate reduction of the fracture. Careful rehabilitation of the patient also contributed to the excellence of the results.