Recombinant human erythropoietin (rHu-EPO) was given during 12 to 20 months in 15 long term haemodialysis anaemic (mean Hb: 6.6 +/- 1 g/dl) patients who required no blood transfusion. Patients over 65, or with severe arterial disease or with uncontrolled hypertension were not included in this trial. Correction of anaemia (mean Hb 12.1 +/- 0.6 g/dl) was achieved in all patients and maintained all along the study. An improved sense of wellbeing and increased exercise tolerance were reported by all patients. Appropriate maintenance dosage of rHu-EPO was 74 +/- 6 U/kg i.v. twice weekly. High dose oral and/or intravenous iron therapy was necessary in the absence of previous marked iron overload. One retinal venous thrombosis was the sole severe side-effect encountered. A slight but significant increase of blood pressure was observed with the need of intensifying previous anti-hypertensive therapy in one patient and of starting one in one another. Fine adjustment of the dry weight was necessary to maintain blood pressure in the normal range. Heparin requirements increased in the majority of patients because of hollow fibre clotting but there was no evidence of decreased efficacy of dialysis. In two patients clotting of arteriovenous fistula was not obviously related to the rHu-EPO treatment.