Eighty-eight consecutive patients undergoing total knee arthroplasty (TKA) were reviewed retrospectively and divided into two groups. Group I (64 patients) had both knees replaced simultaneously by one team in a single procedure while Group II (24 patients) had 2 operations staged about 7 days apart. The blood loss, operative time, knee functional score, period of hospitalisation and complications were documented in order to compare the 2 groups. Performing simultaneous bilateral TKA (Group I) did not increase the incidence of operative or post-operative complications. Equally, the functional score and mean intra- and post-operative blood loss were not influenced. The operative time and duration of hospitalisation were significantly shorter in Group I than in Group II. On the basis of the results of this study, it appears that simultaneous bilateral TKA is beneficial.