Local pain due to subcutaneous erythropoietin (EPO) injection into the thigh was studied using a verbal score ranging from 0 to 4. Equivoluminous doses of epoetin-α (Cilag) and epoetin-β (Boehringer) were compared in 2 controlled single-blind experiments: 10 dialysis patients were treated at random for 4 weeks at consecutive sessions with both brands of EPO, and 40 patients were treated in 1 session only with the 2 brands simultaneously. Pain scores were 1.12 ± 0.28 versus 0.15 ± 0.06 (p < 0.05) and 1.75 ± 0.19 versus 0.08 ± 0.04 for epoetin-α and epoetin-β, respectively (p < 0.001). Treatment acceptance was 48% for epoetin-α versus 83% for epoetin-β (