The aseptic loosening has emerged as one of the most common and serious long term complications, which requires the revision of total hip replacement arthroplasty. We studied the radiologic finding of the aseptic loosening in 79 patients of uncemented total hip replacement arthroplasty which had been performed in our hospital from March 1991 to December 1994. We evaluated the white reaction lines, osteolysis state, translation and migration in postoperative and last follow-up radiographies. The white reactive lines around the femoral stem and the acetabular cup were most frequent in zone IV and zone II. But it was not progressive and need more long term follow-up evaluations to confirm whether these lines are related to loosening or not. In assessment for stable state, the more stable at initial fixations, the better state of long term stability. Some patients have pain without loosening but all patients with loosening have pain. Press fit is the most important factor of the late stability. The osteolysis is not directly proportional to femoral loosening in this study, but it might be due to short follow up time.