In 22 patients with femoral neck fractures 99mTc-MDP scintimetry was performed before operation and again shortly after operation; in 17 of these patients the investigation was repeated after four months. Six patients with increased uptake in the femoral head before operation and eight with decreased uptake had similar results at the first postoperative investigation. Of eight patients with an intermediate uptake before operation, two showed increased and six decreased femoral head uptake after operation. It is concluded that for the patients in the group with intermediate femoral head uptake before operation, the operative procedure probably influenced the postoperative blood supply of the femoral head.