Seventeen young adults with subcapital femoral neck fractures that occurred after injury and with no signs of osteoporosis were treated conservatively (2 cases) or by closed reduction and internal fixation. Evaluation of the results was based on clinical, radiological and scintigraphical examinations. The incidence of non-union was 24 per cent (4/17) and the incidence of avascular necrosis of the femoral head was 41 per cent (7/17). The total failure rate was 41 per cent as all fractures with non-union also had avascular necrosis. It was found that reduction was the most important factor determining the outcome, as only 17 per cent (2/12) of fractures with a good reduction subsequently developed non-union compared with 100 per cent (5/5) with malreduction. High-velocity injury was no more crucial than low-velocity injury. The final outcome of femoral neck fractures in young persons did not differ from the known outcome in elderly persons.