Three surgical approaches to primary total hip arthroplasty (THA) have been in use since Charnley popularized the transtrochanteric approach. This study was designed to examine the difference in morbidity between the transtrochanteric approach and the anterolateral approach in primary THA. Information on 891 patients who underwent primary THA performed by a single surgeon was collected prospectively between 1998 and 2003 using a modified SF-36 form, preoperatively, intraoperatively, and at 3 months postoperatively. The transtrochanteric group had higher morbidity and more patients who were dissatisfied with their THA. There was a greater range of motion in the anterolateral group.