Total knee arthroplasty is indicated for painful joints, with or without deformity, secondary to rheumatoid arthritis, osteoarthritis, traumatic arthritis, and certain other forms of nonseptic arthropathy. Many patients with arthritic knees have symetrical involvement and thus require a bilateral operation. Staged bilateral arthroplastis were performed with many drawbacks such as prolonged hospitalization, repeated anesthetic risks, and increased cost. Simultaneous bilateral arthroplasty under one anesthesia by two teams offers several advantages over staged procedure. We studied the results of 145 total knee arthroplasties, performed over a five-year period, to compare unilateral(group I;45 knees), staged bilateral(group II; 24 knees), and simultaneous bilateral arthroplasties(group III; 76 knees) by 2 team approach. Duration of mean follow-up was 1 year and 9 months. The results are as flollows; 1. The mean anesthetic times were 189 minutes, 312 minutes, and 218 minutes for the group I,II,III, respectively. 2. The mean blood loss was 1075ml for the group I, 1644ml for the group II, and 1902ml for the group III. 3. The hospitalization period was 74.1 days in two stage procedures, while it was 48.6 days in simultaneous bilateral procedures. 4. Knee scores by Knee Rating Scale of Hospital for Special Surgery were increased to 85.3 points, 80.7 points, and 85.4 points for group I,II,III, respectively. 5. There were no difference in complication among three groups. 6. Group III had advantages such as reduced anesthetic risk, reduced rehabilitation period, and decreased cost.