Acute renal failure remains a common and life-threatening disease with a very high mortality. Renal replacement therapy only provides supportive care. The purpose of this review is to discuss the indications and complications of renal replacement therapies in acute renal failure. Various controversial issues such as biocompatibility of membranes, adequacy of dialysis and utilization of continuous renal replacement therapies in acute renal failure are also covered. The nutritional needs of a patient with acute renal failure receiving renal replacement therapy are also explained. Finally, the outcome of patients with acute renal failure requiring dialysis is discussed.