In view of the recent interest in weekly erythropoietic regimens and the lack of studies directly comparing the available agents, the clinical effectiveness of darbepoetin-a (DA) and epoetin-beta (EB), when administered via the subcutaneous route on a weekly basis, after conversion from thrice-weekly subcutaneous EB, was studied. In this 9-mo, single-center, randomized study of an unselected hemodialysis population, anemia was managed with a computerized decision-support system. Per-protocol analysis of the 81 patients in each arm who completed the study showed similar hemoglobin outcomes between treatment arms, both at randomization and at the end of the study. After conversion from thrice-weekly EB to DA (at a ratio of 200 IU:1 mu g, at which products are cost-neutral in the European Union), a significant fall in dose from a mean of 0.59 mu g/kg per wk after randomization to 0.46 mu g/kg per wk in the last month (P = 0.002) was observed; in the comparator arm, the reduction in frequency of administration of EB was associated with a significant dose increase from a mean of 107.5 to 133.2 IU/kg per wk (P = 0.002) during the same period. At hemoglobin stability, mean EB dose was found to be 44% higher than DA dose (when multiplied by 200). Similar significant dose differences were apparent in a modified intention-to-treat analysis. The study demonstrated that, under a decision-support system, both products were capable of adequately maintaining hemoglobin outcome when administered on a weekly basis but with significant dose differences at 9 mo.