Twenty-six primary hip prostheses were implanted in nineteen patients with a diagnosis of aplastic anemia between January 1990 and December 1992. The preoperative diagnosis were osteonecrosis of the femoral head in twenty-five hips and femoral neck fracture in one. The duration of follow-up was minimum of fours years. Preoperatively, the average Harris hip score was 56. At four years postoperatively, the average score reached 87. At this time, twelve hips were rated excellent, eleven good, two fair, and one poor. One patient who received a bipolar arthroplasty showed an intrapelvic protrusion of the acetabular component. Another bipolar fixed with Boneloc cement was performed due to femoral neck fracture. There was no migration of component, subsidence, radiolucency or osteolysis in three hips with hybrid fixation. No sign of migration of acetabular component was seen with uncemented prosthesis. Two hips with HA coated acetabular components showed a progressive radiolucent line. Progressive retroacetabular osteolysis was found in one hip at zone I and II. There were neither cases of infection nor hemorrhage complications. Two patients died of pneumonia and sepsis, respectively, at fifty-three and fifty-seven months postoperatively. It appears that fatty marrow conversion of proximal femur and pelvis does not affect the survival of cemented and uncemented fixation, but long-term follow-up is needed to validate our view. We have demonstrated that the hip arthroplasty in most patients with aplastic anemia can be successful despite the fact that hematologic characteristics of aplastic anemia seem to indicated a high risk for hemorrhagic complication and infection. In conclusion, we strongly recommend hip arthro-plasty if the patients has a painful hip joint, regardless of severity of aplastic anemia whose prognosis may be disappointing.