This was an open-label multicentre study of recombinant human erythropoietin (r-HuEPO) in 116 children aged 6 months to 20 years with anaemia of chronic renal failure undergoing haemodialysis. Haemoglobin concentration at entry ranged from 3.4 to 9.5 g/dl. r-HuEPO was given intravenously two or three times per week, the starting dose being 75 U/kg per week. This was subsequently titrated in steps of 75 U/kg per week with the goal of increasing haemoglobin concentration at the rate of 1 g/dl per 4 weeks into the range 9.6-11.2 g/dl (6-7 mmol/l), with treatment then continued for up to 1 year with the aim of maintaining the haemoglobin concentration within the target range. Of the 115 children in whom efficacy could be evaluated, 93 (81%) achieved the target haemoglobin and a further 6 had a rise in haemoglobin concentration of at least 2 g/dl. At 52 weeks, the median maintenance dose for children < 30 kg was 225 U/kg per week, compared with 107 U/kg per week for children > or = 30 kg. Analysis suggested that 150 U/kg per week would have been a more appropriate starting dose. The mean transfusion requirement fell from 8.9 to 0.7 units/patient per year. Of the 22 patients who failed to reach the target, 15 went on to transplantation and left the study prematurely. Sub-group analysis showed that similar doses lead to similar rates of rise in haemoglobin regardless of the severity of the original anaemia. Assessment of quality of life suggested that this may have improved with r-HuEPO.(ABSTRACT TRUNCATED AT 250 WORDS)