In May 2009 for financial reasons, the epoetin product used for hemoglobin (Hb) maintenance in our renal dialysis unit was changed from epoetin beta to epoetin alfa.Although widely believed that the dosage requirements are the same we undertook a retrospective analysis to investigate whether the dosage requrements in chronic rena fai ure pat ents were comparable for both preparations.We studied 128 stable end-stage renal failure patients on hemodialysis (three times per week) receiving erythropoietin therapy to maintain their Hb at 1 1-12.5 g/dL.Patients were excluded if within the study period they developed signs of infection bleeding, required blood transfusion, were under-dialyzed, or recuired hospital admission.Regular monthly Hb concentrations and hematocrit (Hct)levels were measured for each patient.The weekly EPO index (defined as weekly epoetin dose/mean monthly Hct)was dericed for each patient, before and after regime change.Of the 128 patients in end-stage renal failure, 79 were included in the study.There was no significant difference between the two preparations in terms of Hct level achieved (p =0.15).However, the median weekly epoetin dose requirement increased from 6733 (range 750-30,000)IU/week to 9000 (250-30,667) IU/week (p < 0.001).EPO index similarly increased from 20,465 (2500-130,846) IU/week/% to 27,073 (729-98,937)IU/week/% (p < 0.001).Our study showed that a higher dose of epoetin alfa was needed to maintain target Hb concentrat on.