Aseptic loosening is most common coinplication of the cemented total hip arthroplasty and it's incidence is higher with twenty one to fifty seven percent in patients who are younger than sixty years old. Recently, cementless total hip arthroplasty in widely used to get biologic fixation instead of mechanical fixation due to bone cement. The absolute prerequisites for successful cementless total hip arthroplasty are press fit of the implant, immediate stability and adequate immobilization. The purpose of this study was to assess radiologic evaluation of surgical fitness and stability of the implant, and clinical evaluation by Harris hip rating score. The authors analysed twenty eight patients (thirty cases) of cementless total hip arthroplasty using Harris-Galante porous coated prosthesis from Jan. 198S to Aug. 1989 after minimum 18 months follow up. The average age was 44.7 years (range, twenty-two to seventy-eight years). There were twenty-four male and four female. The preoperative diagnosis was avascular necrosis of the femoral head in 14 cases, sequele of the femoral neck fracture in 5, 2ndary to ankylosing spondylitis in 3, aseptic loosening of Wagner surface replacement arthroplasty in 3, and 5 other cases. Postoperative follow up ranged from 18 months to 61 months with average 36 months. The preoperative evaluation were assessed by three methods:Engh and Bobyn's method, Sportono and Romagnolis method, and Dorr's method. Thirty Harris-Galante femoral stem were combined with Harris-Galante acetabular component in 19 cases and bipolar component in 11 cases. The discussion of acetabular side were not included for this investigation. The obtained results were as follows:1. The press fit fixation at isthmus was twenty-two cases (Fit 1A in 18 and 1B in 4) and eight cases (Fit 2A in 5 and 2B in 3) without press fit fixation according to category of the femoral stem fit. 2. Among twenty two press fit fixation, bony ingrowth fixation was 19 cases and fibrous ingrowth in 3 cases. Five cases out of eight cases without press fit fixation were fibrous ingrowth, one bony ingrowth and two questionable instability. 3. The average Harris hip score improved from 57.5 points preoperatively to 90.4 points postoperatively. The pain was improved from preoperative 20.3 points to postoperative 40.7 points:Function from preoperative 29.8 points to postoperative 40.8 points:Motion from preoperative 3.8 points to postoperative 4.8 points. 4. Clinical result by Harris hip evaluation were excellent in 19 cases, 9 good and 2 fair. 5. The average Harris hip score according to fit category of the femoral stem was 92.7 points in Fit 1A, 87.9 points in 1B, 86.3 points in 2A, and 85.2 points in 2B. 6. The average Harris hip score according to fixation category of the femoral stem was 92.7 points in bony ingrowth fixation, 86.7 points in fibrous ingrowth fixation and 80.9 points in questionable instability. 7. The average Harris hip score was 91.1 points under 60 years age and 86.7 points above 60 years age. 8. Among three methods for preoperative evaluation, Engh and Boby'n method was more reasonable than Sportono and Romagnoli and Dorr's method. 9. Post operative complication was thigh pain in 6 cases, proximal stress shilelding in 21 cases, 1 linear calcar fracture during operation, 1 supracondylar fracture and femoral shaft fracture below prosthetic tip and 1 heterotopic ossification. Above results suggest which cementless total hip arthroplasty could get satisfactory result if patient has preoperatively good bone quality and the press fit fixation in the isthmus at operation is achieved.