Renal dysfunction following cardiopulmonary bypass is a frequent complication of open heart surgery. Acute renal failure requiring dialysis occurs in approximately 1.5% of patients following cardiac surgery and remains a cause of major morbidity and mortality. Method: Sixty-five patients of either sex in the age group of 10-50 years scheduled to undergo various cardiac procedures were included in this study. All patients had normal preoperative levels of serum creatinine, blood urea nitrogen, blood glucose levels, urine analysis, 24 hour urinary protein < 200 mg, and normal 24 hour creatinine clearance. After surgery, patients were transferred to an intensive care unit for postoperative management and monitoring. Patients were shifted to cardiovascular and thoracic surgery ward as soon as their clinical condition permitted. Blood urea nitrogen, serum creatinine, 24 hour creatinine clearance was performed on day one and day seven of postoperative period. Result: Postoperative oliguric acute renal failure was 7.7% and overall mortality was 6.1%. We found no association between aortic cross clamp time and postoperative renal dysfunction. Conclusion: Optimisation of cardiac performance post cardiopulmonary bypass seems to be the most important factor in the prevention of postoperative renal dysfunction in patients requiring total cardiopulmonary bypass.