Background.Anaemia in haemodialysis patients can be effectively treated with erythropoietin.We investigated whether subcutaneous (SC) epoetin β administered once weekly was as effective as the same weekly dosage given in two to three divided doses.Methods.One hundred and fifty-eight patients (delivered Kt/V > 1.0, where K=dialyser-renal urea clearance, t=dialysis time and V=filtration volume,obtained by urea kinetic modelling) were randomized to treatment with SC epoetin β either once weekly (n=118), or to their original dosage two or three times weekly (control group, n=40) for 24 weeks.All patients received intravenous iron supplementation when necessary.Results.Eight-eight patients in the once weekly group and 30 patients in the control group were treated for at least 16 weeks and are included in the analysis.Stable haemoglobin levels were maintained without epoetin dose increases in 73% of patients in both groups.Mean haemoglobin levels at randomization and after 16 and 24 weeks were 11.4, 11.1 and 11.1 g/dl,respectively, in the once weekly group compared with 11.2, 11.3 and 11.2g/dl, respectively, in the control group.The mean weekly epoetinβ dosages at randomization and after 16 and 24 weeks were 102, 103 and 106 IU/kg bodyweight, respectively, in the once weekly group compared with 109, 109 and 115 IU/kg bodyweight, respectively, in the control group.No statistically significant between-group differences were apparent for changes in haemoglobin levels or epoetin β dosages at week 24.Conclusions.Once weekly SC administration of epoetin β is as safe and effective in maintaining haemoglobin levels in stable haemodialysis patients as two or three times weekly administration of the same total dose.By using the once weekly regimen, patients can avoid up to 104 injections per year.This would reduce clinic time for patients who do not self administer, and may also encourage self-administration and improve overall compliance.