A study of 123 patients with impacted, subcapital femoral fractures was undertaken to determine the natural history of this injury. It was found that the angle of the fracture, the degree of valgus and the degree of retroversion were without significant effect on the incidence of subsequent disimpaction. Age was important, with a 20 per cent incidence of disimpaction in patients over the age of 68 years. In patients younger than this the incidence was only 2 per cent. These results indicate that conservative treatment may be appropriate for some younger patients, but the advantages of this approach must be compared with the medical, social and economic benefits of early mobilization that the relatively simple operative procedure permits.