The purpose of this study was to determine if any differences existed in the early complication rate, short term clinical outcome, and total length of hospital stay between patients who had bilateral total hip arthroplasty performed under a single anesthetic (during 1 patient visit to the operating room) and patients who had the procedure performed under 2 anesthetics (during 2 patient visits to the operating room). Patients operated on bilaterally were divided into 3 groups: Group A (1 stage procedure)--hips that were operated on simultaneously (128 hips); Group B (2 stage procedure)--surgeries performed less than 6 weeks apart (126 hips); and Group C (2 stage procedure)--surgeries performed between 6 weeks and 6 months apart (256 hips). All patients were evaluated after an average followup of 1.5 years. There were no differences in operative, early local, or general complications among the 3 groups. In particular, no higher incidence of pulmonary embolism or deep vein thrombosis was found in the 1 stage group. Preoperatively, very stiff hips (total range of motion < 50 degrees) gained significantly more motion in the 1 stage group than in the 2 stage groups, whereas hips with better preoperative motion (total range of motion > 50 degrees) improved the most in Group B, without a significant difference occurring between Groups A and C. The degree of pain reduction was the same in all groups, but patients in the 1 stage group had a significantly better capacity for walking after their procedure. Average total hospital stay was 5 to 6 days less for the patients in Group A than those in the other groups, which, combined with using the operating room only once, resulted in a reduction of overall hospital costs by more than 30% when using the 1 stage procedure.