The article reports on two cases of a typical necrosis of the head of the femur, known as "idiopathic necrosis of the femoral head". Hyperuricaemia was present in both cases. In the first female patient, scintigraphy showed accumulation of activity unilaterally in the region of the ankle joint without any pathological x-ray finding in that region. The necrosis of the head of the femur was atypically associated with a lateral narrowing of the joint space and apposition of the bones at the lateral joint edges. Angiography did not yield any abnormal finding in the hip joint. In the case of the second (male) patient, the necrosis of the femoral head was combined with diaphyseal osteonecrotic changes bilaterally, distal to the femoral shaft, and there was also a diffuse decalcification, not recorded so far, metaphyseally distal to the femoral shaft and proximal at the shaft of the tibia, reaching to the epiphyseal cicatrices. Hyperuricaemia was combined with hyperlipidaemia. In both patients, the hyperturicaemia dropped to normal levels under appropriate medication; in the second patient, this was also true of the hyperlipidaemia and hypercholesterolaemia. No further progress was seen from the time the blood levels had become normal.