The purpose of the current study was to review the results of total knee replacement (TKR) in patients with diabetes mellitus and to test the hypothesis that patients with diabetes achieve inferior results after TKR. From a consecutive series of 5220 primary cemented TKRs, 363 were done in 291 patients with diabetes mellitus. Cefuoxime-impregnated cement was used routinely. The results in the study group were compared with the results in the patients without diabetes who had TKR during the same period. The followup averaged 52 months. Knee scores were higher in patients with diabetes preoperatively (47 versus 38) and postoperatively up to 7 years (80 versus 75). The average preoperative and postoperative pain scores also were higher in patients with diabetes. Four deep infections (1.2%) occurred in patients with diabetes versus 35 deep infections (0.7%) in patients without diabetes. The revision rate (including infections) was greater in patients with diabetes (3.6% versus 0.4 %). Knee and pain scores were similar in patients with insulin-dependent and noninsulin-dependent diabetes. Postoperative function scores, however, were lower in patients with insulin-dependent diabetes. In the study group, all deep infections occurred in patients with insulin-dependent diabetes.