This study analyses the prognostic factors associated with survival in 70 patients who developed acute renal failure following surgery for an aortic aneurysm. Forty-nine patients (70 per cent) had surgery for a ruptured aortic aneurysm and 21 patients (30 per cent) had an elective procedure. Fifty-nine patients received haemodialysis. Thirty-three patients (47 per cent) survived the episode of acute renal failure. Six of these thirty-three patients died within three months of recovering from acute renal failure, giving an overall survival of 27/70 (39 per cent). A stepwise logistic regression analysis showed that the following factors significantly adversely affected survival: a need for inotropic support, ventilation for more than three days and age over 65 years. A model developed using these variables provided a basis for predicting outcome.