The three-dimensional shape optimization of cemented total hip arthroplasty (THA) was introduced in this paper. The P-version Finite Element Method (FEM) combined with an optimization procedure was used to minimize the peak stress in the bone cement near the tip of the implant. Six-design variables were used in this study. Each variable represents the dimension of the medial-lateral width and anterior-posterior width of the three levels (proximal, distal and middle) of cross sectional area of the prosthesis. The results of the design optimization showed considerable reduction in stress concentration compared to the initial design that is currently used clinically.