Twenty-seven adolescents with 29 femoral shaft fractures, between the ages of 10 and 16 years, were treated with closed flexible Ender intramedullary nailing from 1989 to 1992 in our clinic. In one patient who had a fracture of the distal third of the femoral shaft, the nail was inserted proximal to distal (antegrade nailing). In the other patients, the nails were inserted distal to proximal (retrograde nailing). Clinical and radiological follow up averaged 32 months (18-56 months). Hospitalization averaged 15 days (7-28 days). All fractures healed with one significant leg length discrepancy of 1.7 cm in a patient who had developed osteomyelitis. There was no significant angulation or malrotation. All patients had a normal gait and were able to participate in full activities. There was one deep wound infection in a patient with an open fracture of the femoral shaft. There were no non-unions, delayed-unions or psychological complications. For this age group, this treatment of femoral shaft fracture should be considered owing to the functional recovery with low morbidity and cost, providing early ambulation, early discharge from hospital and early return to school.