One hundred and two fractures of the femoral shaft, including eighteen pathological fractures, in 100 patients were internally fixed by closed Küntscher nailing. Sixty-eight fractures resulted from motor vehicle accidents; ten were compound. Seventy-five patients were under the age of thirty years and thirty-four had multiple injuries. Sixty-nine fractures were nailed on the day of the accident and the operative technique is described. Complications during and after operations were few. Fifty-eight patients left hospital within four weeks and 77% of those working returned to work in less than four months. There were no wound or bone infections. The results are discussed and it is concluded that, with the correct equipment and careful attention to detail, closed nailing is a straightforward procedure with few complications. Advantages include the wide range of fractures that can be nailed, the short hospitalisation, the rapid return of function to the knee, the early return to work and the absence of infection.