Factors influencing survival in ICU patients with acute renal failure (ARF) requiring dialysis were analysed from data collected prospectively in an ARF registry. A total of 363 patients were analysed. Overall mortality was 79.1% and did not differ between medical and surgical patients. Factors associated with an increased risk of dying included the development of any concomitant organ system failure, the number of failed organs, APACHE II score at the time of renal consultation for medical patients, pre-existing chronic liver disease, and the number of days from ICU admission to institution of dialysis. Male gender reached borderline significance. Survivors recovered renal function and discontinued dialysis in 65.7% of cases. We conclude that mortality rates for ARF in ICU patients continues to be high. Multi-system organ failure (MSOF) occurs frequently and is the major cause of death.