Necrosis of the head of the femur with segmentary collapse after transcervical fractures occurs in 30 to 50% of the cases. Diagnosis of avascular necrosis should be made early before the head collapses. In a clinical and experimental study, we attempted to perform early screening for this complication. We studied 41 fractures of the neck of the femur with technitium scintigraphy with intravenous injections and compared uptake in pathological and normal heads. In the first group of 20 cases of fresh fractures, scintigraphy was performed before operation then repeated every three months to the 36th months later. High uptake we seen in 12 of the 20 cases then returned to normal 12 to 18 months later. Consolidation occurred in all 12 without necrosis. In 8 cases uptake was low initially then rose greatly and remained higher than normal. Necrosis occurred in 6 of these 8 cases. In a second group of 21 patients with a history of necrosis of the head of the femur, uptake was high. Pathologic examination of the surgical specimen after resection for prosthesis showed cell growth around the zone of necrosis. In conclusion, this technique, when possible, would appear to be highly useful to screen for necrosis early.