A variety of joint-preserving operations have been devised to preserve the necrotic femoral head with varying success. Since 1979, the authors studied the effectiveness of vascularized fibula grafting in the treatment of osteonecrosis of the femoral head (ONFH) for joint preservation. Eighty-one of 121 hips with a minimum follow-up period ranged from three years to ten years eight months (mean, five years two months). All patients were evaluated clinically and roentgenographically on the basis of the causes and the stages of the disease. In the clinical assessment, 60 (74%) of 81 hips were rated excellent, 14 (17%) were rated good, six (7%) were rated fair, and one (2%) was rated poor. Overall satisfactory results, including excellent and good, were seen in 74 hips (91%). In the roentgenographic assessment, 57 hips (71%) had improved radiologically, 15 (18%) were unchanged, and nine (11%) were worse. Seventy-two hips (89%) showed roentgenographic improvement or unchange. Roentgenographic results had no significant correlation with the etiologic factors. Vascularized fibula grafting is one of the better alternatives for treating ONFH. It is highly expected that vascularized fibula grafting can prevent the necrotic femoral head from progressing to collapse and promote directly restored vascularization and new bone formation.