Mortality from acute renal failure in critically ill patients remains in excess of 50% despite decades of improvement in supportive care. It is not known whether replacement of other failing organs by non-renal organ transplantation affects mortality in acute renal failure. We retrospectively reviewed the course of 169 patients with acute renal failure managed at a single university medical center over a 1-year period. Measures of disease severity (need for renal replacement therapy, mechanical ventilation or parenteral nutrition, presence of oliguria and APACHE II scores) and final outcome were compared in 97 patients with acute renal failure who did not receive transplants and 72 patients with acute renal failure who underwent non-renal solid organ transplants. Overall mortality was 50.3% and directly correlated with APACHE II score. Compared to nontransplant patients, transplant recipients were younger. more frequently male, and less often oliguric; but the groups were similar in mean APACHE II scores and need for renal replacement therapy, prolonged mechanical ventilation, and parenteral nutrition. Overall, mortality was significantly lower for transplant patients compared to nontransplant patients (34.7% vs. 61.9%, p < 0.05). In nonoliguric acute renal failure and renal failure not requiring renal replacement therapy, mortality was low and similar in both transplant and nontransplant patients. Compared to nontrasplant patients with similar risk factors and similar APACHE II scores, mortality was significantly lower for transplant patients who were oliguric, or who required renal replacement therapy, mechanical ventilation, or parenteral nutrition. Organ transplantation is associated with a survival advantage in acute renal failure when compared to the outcome of critically ill nontransplant patients. The relation between APACHE II scores and survival is altered by transplantation.