We report 24 children with acute renal failure treated with continuous arteriovenous haemofiltration (CAVH) between 1987 and 1991. The median age was 2.9 years (range 3 days to 9 years). The main causes of the acute renal failure were: open heart surgery (n = 11) and liver failure of different origins before and after liver transplantation (n = 10). The indication for CAVH was oliguria or fluid overload in all children. The femoral vessels were used as vascular access in most instances. Different filters were used, depending on the size of the patient and an average ultrafiltration of 130 +/- 89 ml/h was achieved, which resulted in a fluid clearance of 4.0 +/- 2.6 ml/min per 1.73 m2. In 18 patients uraemia was adequately controlled. Nine children survived after recovery of their renal function; 15 (62.5%) died as a consequence of multiorgan failure. We conclude that CAVH is an effective method to support critically ill children with acute renal failure.