The effects of streptozotocin-induced diabetes and insulin on the duration of xylazine-ketamine anesthesia were studied in rats. The duration of anesthesia was significantly reduced in diabetic group as compared to control group. In contrast, the duration of anesthesia in insulin-treated non-diabetic group was not significantly different from control group. The plasma glucose level in control group was increased significantly during and upon recovery from anesthesia as compared to pre-anesthetic levels. The plasma glucose level in diabetic group was not changed during anesthesia; however, it was reduced significantly upon recovery. The plasma glucose level was significantly reduced in insulin-treated group as compared to pre-anesthetic levels. The reduction in duration of anesthesia in diabetic rats is possibly due to enhanced metabolism xylazine and/or ketamine and is independent of plasma glucose level.