This is a followup study of 31 hips in 24 patients from 2 to 11 years after receiving a vascularized iliac bone graft for nontraumatic avascular necrosis of the femoral head. The clinical results according to the Merle d'Aubigne score were satisfactory in 24 (77%) of the hips, whereas the radiographic success rate for all hips was 58%. The extent of the lesion as shown on anteroposterior radiographs was predictive of the eventual outcome. Seven (39%) of 18 hips with a lateral type lesion had satisfactory results, whereas 11 (85%) of 13 hips with a medial type lesion had satisfactory results. All of the hips with a medial type lesion and a lateral head index of greater than 12% had satisfactory results. For the success of this procedure, the lateral buttress of the normal portion in the femoral head was necessary.