Background: This study aims to evaluate clinical results of the prophylactic use of renal dose dopamine infusion in diabetic patients undergoing coronary artery bypass grafting (CABG). Methods: In this prospective randomized study, 40 consecutive diabetic patients who were scheduled for elective CABG were randomized into two equal groups: group 1 received dopamine infusion at renal dose (2.5-4.0 mg/kg/min) starting from induction of anesthesia for 48 hours; group 2 consisted of untreated controls. Standard sternotomy technique using aortic and right atrial cannulation was performed for cardiopulmonary bypass. Results: Daily urine output, fluid balance, serum creatinine, blood urea levels and creatinine clearance were measured at three and five days. In the control group, third and fifth postoperative day, creatinine clearance levels decreased about 24.8±12.3 mL/min and 18.1±10.1 mL/min, respectively. In the dopamine group, creatinine clearance levels in the third and fifth postoperative days increased by 7.7±10.8 mL/min (p=0.005) and 10.7±11.7 mL/min (p=0.001), respectively. Group 1 patients demonstrated less increase in serum creatinine level at three and five days than the controls (p<0.001). Conclusion: Creatinine and creatinine clearance levels, suggestive of renal tubular function, were positively affected by renal dose dopamine infusion started at time of anesthesia induction. Our data may help us to re-normalize the renal functions in the postoperative period in diabetic patients, particularly.