In this study, we have investigated the effects of flow character in cardiopulmonary bypass on the insuline level and glucose metabolism in type II diabetic patients and 30 patients were included in two groups according to the flow character applied: pulsatile and nonpulsatile flow. The parameters studied were insuline and glucose. Measurements were performed in all patients totally three times as in the preoperative period, at the 30th and 60th minutes of perfusion. It was acertained that, in the perfusion period, the glucose levels were stayed at higher levels in the nonpulsatile group and despite a slight increase in the same group, there was not any statistically significance between the two groups in terrms of insuline measurements. Also the cumulative requirements of insuline and glucose were detected in the first 24 hours postoperatively. There was not any statistical difference between the two groups in terms of cumulative glucose requirements were significantly lower in the pulsatile group. These results can show that, pulsatile perfusion in open heart surgery can perform more controllable and stable glucose levels in diabetic patients.