BACKGROUND: There are few epidemiological studies on acute renal failure, and as far as we know none have previously been conducted in Norway. The objective of this study was to evaluate the scope, etiology, treatment and results of dialysis-dependent acute renal failure based on data from the Norwegian National Hospital in 1998. MATERIAL: This study is based on data from a questionnaire applied to all patients (n = 44) treated with dialysis for acute renal failure at the Norwegian National Hospital in 1998. The questionnaire was designed by a group of Norwegian nephrologists in cooperation with the Norwegian Society of Nephrology. RESULTS: The incidence of dialysis-dependent acute renal failure was 54.4 per million population. Men constituted 75% of the patient population. The most common underlying disorders were heart disease, peripheral vascular disease, and cancer. 90% of patients had oliguric acute renal failure, most frequently due to postoperative complications, septicaemia or drugs, and in most cases the aetiology was multifactorial. Patients received on average nine intermittent hemodialysis treatments and stayed on average ten days in the intensive care unit. 30% of the patients were either heart, lung, liver or bone marrow transplanted (renal transplant patients were excluded). The 60 day mortality rate was 41%. INTERPRETATION: The incidence of dialysis-dependent acute renal failure was relatively high in the Norwegian National Hospital patient pool, combined with a significant mortality rate. These findings are comparable with those of other studies.