Patients undergoing major surgical operations are under risk of developing acute renal failure postoperatively. Risk factors for developing postoperative renal failure may be classified as: patient risk factors and surgical risk factors. Patient risk is directly related to preoperative renal function and advanced age. Surgical risk is highest in patients who underwent any surgery with important haemodynamic variations. The cumulative renal injuries from various life events such as nephrotoxic drugs or perioperative renal insult may ultimately lead to irreversible renal injuries or mortality associated with postoperative renal failure. For this reason; preoperative risk stratification and management of patients should be planned carefully, especially before major surgeries; in order to avoid postoperative mortality and morbidity due to acute renal failure