Loosening is the most serious complication of cemented hip replacement with long-term follow-up. So there were several attempts of fixing total hip prosthesis by biological fixation than by cement, and bony ingrowth using porous coated component is one of them. Hip arthroplasty using cementless porous coated femoral stem(Tri-lock(TM)) was performed in 190 patients(210 cases) between June 1984 and April 1990 and we reviewed and analysed 150 cases with follow-up ranged from twelve to seventy-three months. The results are as follows. 1. There were 73 males and 57 females and the mean age at surgery was 46.4 years(19-84 years). 2. The etiological incidence included 75 cases of osteonecrosis, 27 cases of secondary osteoarthritis, 15 cases of fracture of the femoral neck, 15 cases of hip fracture-dislocation, 10 cases of rheumatoid arthritis and 8 cases of tuberculous hip. 3. For acetabular component, we used cemented Muller cup in 29 cases, cementless AML-plus cup in 35 cases and bipolar cup(self centering universal hip) in 86 cases. 4. There was pain on mid-thigh in 6 cases(4.0%) but it was resolved within one year. 5. The press fit of the stem at the isthmus on immediate postoperative anteroposterior radiograph was observed in 90 cases(60.0%) and the stable fixation was achieved in 141 cases(94.0%) finally. 6. There were 9 cases(6.0%) of vertical subsidence more than 5mm. 7. There were 65 cases of first degree stress shield, 57 cases of second degree, and 18 cases of third degree. 8. Heterotropic ossification developed in 9 cases(6.0%) and Brooker's type one was most cmmon. 9. Cortical hypertrophy was observed in 39 cases and they occured commonly at Gruen's zone two and six. 10. Endosteal bone formation was observed in 46 cases and it's occurence at Gruen's zone three, four and five, that is near the stem tip, were seventy-two percent. 11. There were 4 cases(2.67%) of intraoperative undisplaced fracture of femur. 12. Average Harris hip score was 51 preoperatively and 93 postoperatively. In conclusion implant fixation using porous coating is a reliable procedure for good bony fixation and clinical results.