Renal dysfunction is associated with markedly increased risk for both mortality and morbidity in patients undergoing coronary artery bypass surgery (CABG), especially in elderly patients. In the current study, we aimed to determine the impact of prophylactic preoperative hemodialysis on operative outcome in patients with mild renal dysfunction. Between March 2002 and May 2005 a total of 64 patients, all of whom were more than 70 years of age and with preoperative creatinine levels greater than 2 mg/dL, underwent primary elective on pump coronary artery bypass surgery. The mean age was 76.3 ± 6.4 (range 70–83). The patients were prospectively allocated into two groups. Group A was the dialysis group (31 patients) and preoperative prophylactic hemodialysis was carried out in all patients. Group B (33 patients) was taken as a control group without preoperative hemodialysis. During the present study, 10 patients died (15.6%) in the hospital. In the postoperative period mean levels of creatinine were found to be decreased in dialysis group. (2.3 ± 0.8 mg/dL vs. 3.4 ± 0.2 mg/, P= 0.037). The incidence of overall morbidity (such as acute renal failure, need of postoperative dialysis, low cardiac output and multiple organ failure) were also found to be decreased in dialysis group. We conclude from the present study that preoperative renal dysfunction and advanced age increase the risk of mortality and morbidity after on-pump coronary artery bypass surgery. We believe that perioperative prophylactic hemodialysis is an easy and effective method and it decreases both operative mortality and morbidity in elderly patients with renal dysfunction.