BACKGROUND: The incidence of acute renal failure requiring dialysis is not known in our country. The criteria for acute dialysis are not uniformly accepted, neither is there consensus on dialysis strategy in critically ill patients. We describe the acute dialysis activity in our hospital in 1999. MATERIAL AND METHODS: We have retrospectively recorded the indications for dialysis and the course and hospital mortality in all patients treated with acute dialysis in 1999. RESULTS: 108 patients were treated with 670 dialysis procedures; the incidence was 20.5 per 100,000 inhabitants. Continuous veno-venous haemodiafiltration accounted for 37% of all treatments. In 50% of the patients acute renal failure occurred after surgery or serious infections with a mortality of 57% and 62% respectively. Total dialysis mortality was 45%. The mortality in patients with malignancy and peripheral vascular disease was 90% and 75% respectively. 10% of the patients needed chronic dialysis. INTERPRETATION: The incidence of acute dialysis was higher than previously reported from European countries and may be related to the general increase in active treatment of patients with complicated diseases. The mortality rates are persistently high. Close cooperation between nephrologists and intensivists in the treatment of these patients is essential.