The objective of this study was to analyze the efficacy of continuous veno-venous renal replacement therapies in neonates and children. We analyzed 10 episodes of acute renal failure in 9 patients, between 7 days and 2 years of age and weighing between 2.9 and 13 kg, treated with continuous veno-venous renal replacement therapies (hemofiltration or hemodiafiltration) by using a BSM-32-IC (Hospal) monitor and two types of hemofilters, Miniflow of 0.04 m2 (Hospal) and FH22 of 0.2 m2 (Gambro). We used a blood flow between 15 and 40 ml/min and obtained an ultrafiltration rate of 190 +/- 61 ml/hour. The mean life of the hemofilters was 16 +/- 14 hours, with the duration of the technique between 5 and 58 hours. In three episodes the technique was ended because of normalization of renal function. All patients tolerated continuous renal replacement therapies without important secondary effects (one patient had moderate ischemia of the leg because of erroneous arterial catheterization, 3 patients had electrolyte alterations. 1 patient had hypothermia and 5 patients needed platelet transfusions). Seven patients died because of shock and multiple organ failure which was not related to the technique. Continuous veno-venous renal replacement therapies are useful in the treatment of critically ill children. Veno-venous techniques can be used in term neonate and infants.