Efforts to reduce production of polyethylene wear debris are critical to improve the long-term success of total hip arthroplasty. A variety of factors affect the wear between the femoral head and polyethylene acetabular component. Methods of measuring smoothness of femoral heads, the performance of metal alloys and ceramic materials, and the clinical experience comparing the performance of cobalt chrome and ceramic materials are discussed. The rationale for the clinical use of ceramic materials in young, active patients is justified by the current laboratory data from wear testing experiments, but awaits clinical validation.