Objective:To evaluate the outcome of total hip arthroplasty (THA) with cementless cups and femoral head autografts for patients with hip dysplasia and osteoarthritis.Methods: Between 1995 and 2002, we implanted 23cementless cups and femoral head autografts in 20 patients with hip dysplasia and osteoarthritis. In this study, a retrospective study was made on 21 hips in 20 patients (18females and 2 males, aged 50 years on an average) with developmental hip dysplasia treated by THA with acementless cup and femoral head autograft. The acetabular cup was placed at the level of the true acetabuinm and all the patients required autogenous femoral head grafts due to acetabular deficiency. The average rate of the acetabular cup covered by the femoral head autograft was 31%(ranging from 10% to 45%). Eight hips had less than 25%cup coverage and thirteen between 25% and 50%. The average follow-up period was 4.7 years (range, 1-8 years).The replacing outcome was evaluated by modified Harris hip score. Preoperative and follow-up radiographs were made.Results: All the autografts were united to the host bones. No autograft was collapsed or no component from the hip was loosed in all the patients. According to the modified Harris hip score, the average hip score increased from 46 before operation to 89 at the final review. Before operation, the leg-length discrepancy was greater than 2 cm in all the patients except one with bilateral hip dysplasia.After operation, only 2 out of 20 patients had a leg-length discrepancy greater than 1 cm. Three hips showed minor bone resorption in the lateral portion of the graft, which did not support the cup. Three hips developed Grade 1Brooker heterotopic ossification and one developed Grade 2.Conclusions: THA with a cementless cup and a femoral head autograft for patients with osteoarthritis resulted from hip dysplasia can result in favorable outcomes. This method can provide reliable acetabular fixation and restore the acetabular bone stock in patients with developmental hip dysplasia when the cementless cup covered by the graft does not exceed 50%.