We studied about 437 patients(620 hips) who were diagnosed osteoncrosis of the femoral head in Kyung Hee University Hospital during last 15 years and analysed the epidemiologic distribution and relation with other diseases. In 437 patietns, nontraumatic femoral head necrosis(NTFHN) were 340 patients(77.8%) and traumatic femoral head necrosis(TFHN) were 97 patients(22.2%). The male was more affected in ratio of 4:1, especially higher in NTFH about 4.6:1. The peak incidence of age distribution was 4th and 5th decades. The most frequent probable etiologic factors in NTFN was idiopathic(137 patients, 40.3%) and followed by alcoholic(124 patients, 36.5%), steroid induced(53 patients, 15.6%). The cases of bilateral involvement in NTFHN were 182 patient(53.5%). The steroid induced cases(69.8%) were higher than other cases in bilaterality. Liver disease was the most frequent associated disease and it was followed by diabetes mellitus and renal disease. In steroid induced cases, the underlying causes of its medication were nephrotic syndrome(12 patients), arthralgia(8 patients) and dermatologic diseases(7 patients), etc. The abnormal findings of selologic studies in NTFN were hyperlipidemia(28.1%), hyperuricemia (17.0%) and increased transmainase(18.5%) and there was contact relationship between hyperilipidemia and increased transmainase. Marked declination of Harris score was found between stage II and stage III in the course progression of NTFHN. The annual incidence of femoral head osteoncerosis increased gradually.