The purpose of this study is to evaiuate the results of the reconstruction of acetabular bone defect with morselized bone graft and screw fixed hemispherical cup in revision of failed acetabular cup. Thirty four revisions of an acetabular component that had been performed in 34 patients between 1988 and 1993 at SNUH, and had followed more than four years were included in this study. The revised acetabulum was evaluated clinically by Harris hip score and radiologically by evaluating the osseous union, incorporation and resorption of graft, the amount of migration and cup angle change of revised components and periacetabular radiolucency. The mean Harris hip score was improved 52 to 84. All of the bone grafts united by 6.4 months and incorporated by 13.1 months. The graft bone resorption less than onefourth of the initial graft thickness was 91.2% (31 cases). There was no significant difference between pure allograft and allograft mixed with autograft in clinical and radiological results. Of 34 cases, 2 cases (5.9%) required rerevision of acetabulum for aseptic loosening. The two complications, postoperative infection and trochanteric bursitis were managed successfully with conservative methods. The results of the present study confirm the success of revision of the acetabulum with use of a hemispherical component stabilized with multiple small screws and morselized bone grafts filling bone defects.