From January 1975 to December 1990, 141 renal transplants were performed in 129 children. There were 72 boys and 57 girls, aged two to 17 years. Osteonecrosis occurred in seven patients, in the following sites: the femoral head in four children, including two bilateral cases; and the femoral condyle in three children, with two bilateral cases. The mean period from transplantation to the diagnosis of osteonecrosis was 18 months. The osteonecrosis group was compared to the control group and no statistically significant differences were found except in the serum cholesterol levels. The corticosteroid dosage in particular, showed no correlation with the occurrence of osteonecrosis.