OBJECTIVE Assessment of the effects of haemofiltration during cardiopulmonary bypass (CPB) in coronary artery bypass grafting (CABG) on the renal function and correlation with interleukin 6 (IL6) and interleukin 10 (IL10) levels. METHODS Seventy-nine patients scheduled for elective CABG were prospectively randomised into two groups. Group A with a haemofilter attached to arterial line of the CPB circuit and group B without a haemofilter. The two groups were comparable in their symptoms, sex, and previous history of myocardial infarction, left ventricular function, cross-clamp time, bypass time and total grafting per patients. Blood urea and creatinine levels were measured the day before operation, 12h after operation and on the 3rd postoperative day. IL6 and IL10 were measured in blood samples collected 1h before surgery, on arrival to ITU and after 12h. IL6 and IL10 levels were measured using ELISA test. RESULTS High levels of IL6 (>100 pg/ml) postoperatively were associated with increased incidence of renal dysfunction (p<0.017). Additionally, high IL10 (>30 pg/ml) levels postoperatively were associated with increased incidence of renal dysfunction (p<0.014). There were no effects of the haemofilter on postoperative IL6 and IL10 levels. Use of haemofiltration during CPB was found not to be protective against renal dysfunction (p<0.071). CONCLUSIONS Haemofilter use during cardiopulmonary bypass does not have a protective effect on postoperative kidney function. Haemofilter has no effect on the level of IL6 and IL10.