Recently, Prosthetic replacement of hip was recognized as a reliable technique for the treatment of avascular necrosis of femoral head in adult. There were many reports about post-operative evaluation of functional difference between hemiarthroplasty and total hip arthroplasty and which revealed that the revision rate for the total hip arthroplasty was less compared with the femoral endoprosthesis. Also, controversy was existed between the porous coating system and bone cement fixation. In order to evaluate the functional difference among each prosthetic replacement, authors reviewed the result of 10 cases of cementless unipolar endoprosthesis (abbreviated as UE), 10 cases of cementless bipolar endoprosthesis (abbreviated as BE), and 25 cases of cementless total hip replacement arthroplasy (abbreviated as THRA), performed at Department of Orthopaedic Surgery, Soon Chun Hyang University Hospital, during the period from September, 1985 to August, 1988. The following results were obtained: 1. The incidence was higher in 6th decade in UE, THRA groups, 4th decade in BE group. 2. The average follow up of UE, BE, and THRA groups were 30.7, 15.2, and 16.9 months, respectively. 3. By radiological classification of Marcus et al., the average stages of UE, BE, and THRA were 4.9, 4.0, and 5.3respectively. 4. According to Harris hip rating system, post-op. Harris scores were increased as much as 33.1, 37.2, and 43.4 in UE, BE, and THRA groups respectivelycompared with pre-op. score. 5. In this study, the last follow up results of hip function in BE, and THRA groups were better than that evaluated at 6 months after surgery in most cases. 6. External rotation, which was one of needed motion in cross leg sitting position, was significantly influenced by the degree of excision of joint capsule, the type of replacement prosthesis, the regimen of post-op. starting exercise, and a history of previous surgical treatment. 7. Because serious complications were not developed at recent follow up, the UE, BE, and THRA groups showed insignificant difference in functional difference in prosthetic replacement.