Optimal route and frequency of administration of recombinant human erythropoietin (rHuEPO) have not yet been determined. There is some evidence to suggest that subcutaneous administration of rHuEPO may be more effective than the intravenous route in reversing renal anaemia. It is also unclear whether rHuEPO is more effective when given by a large intermittent dose or by more frequent multiple divided doses. We have compared the effect of twice weekly versus once weekly subcutaneous administration of rHuEPO in two groups of haemodialysis patients. At the end of 12 weeks of treatment with rHuEPO, the mean haemoglobin levels had risen from 6.9 ± (SD) 0.7 to 8.9 ± 1.3 g/dl in the once weekly group and from 7.2 ± 1.0 to 9.3 ± 1.6g/dlin the twice weekly group. The average doses of rHuEPO used during the study were 127 + 6 and 115 ± 18 U/kg body weight/week for the once weekly and twice weekly groups, respectively. Subcutaneous administration of low-dose rHuEPO is effective in reversing renal anaemia. Similar responses were obtained with once weekly and twice weekly regi