[Objective]To discuss the outcome of acetabular protrusion after total hip arthroplasty. [Method]Fifteen patients(M=7,F=9) having painful acetabular protrusion received total hip arthroplasty with reinforcement of the acetabulum with bone grafts(autogenous or allogeneous bone).The results were reported at 1~4 years(mean,3 years) of follow-up.Of the 15 cases,5 were mild protrusion and 10 were moderate protrusion.The Harris hip-rating and radiographs were taken pre-and postoperatively. [Result]The average Harris hip-rating was improved from 45 points(range,39~60 points) preoperatively to 85 points(range,70~100 points) postoperatively.The average preoperative protrusion of the femoral head medial to the Kohler line was 8.8 mm(6~18 mm).The average postoperative placement of the prosthetic femoral head was 10 mm(6~13 mm) lateral to the Kohler line.None acetabulum prothesis failure or bone grafts absorption was seen.The grafts were well incorporated on radiograms in all patients one year after operation by radiographs. [Conclusion]Good results can be obtained in hips with acetabular protrusion after reconstructed with autogeneous or allogeneous bone grafting and total hip arthroplasty.