From August 1976 to February 1997, we have experienced 29 cases of rapidly destructive coxarthrosis in 23 patients who represented severe hip pain and destruction of the femoral head more than 50% within one year. The retrospective analyses of clinical, radiographic and operative findings of 2090 hips in 1534 patients, who have been diagnosed as ischemic necrosis of femoral head were performed to investigate the correlation between ischemic necrosis of the femoral head and rapidly destructive coxarthrosis. The incidence of rapidly destructive coxarthrosis was 1 % of the overall ischemic necrosis of the femoral head. The average duration of hip pain was 9 months. The average age of the patients was 56 years old and most of them were male. The cultures of synovial fluid for bacteria were negative in all cases except one case of non-pathogenic organism. But, the erythrocyte sedimentation rate and C-reactive protein were elevated. The pathologic findings were not different from the ischemic necrosis except the destruction of articular cartilage. Therefore, we concluded that rapidly destructive coxarthrosis is a subtype of ischemic necrosis of the femoral head.