This single-arm study will assess the efficacy and safety of intravenous (IV) Mircera when administered for the maintenance of hemoglobin (Hb) levels in participants with chronic renal anemia. Individuals currently receiving maintenance treatment with epoetin alfa or darbepoetin alfa will receive monthly injections of Mircera, with the starting dose (120, 200, or 360 micrograms [mcg] IV injection) derived from the dose of epoetin alfa or darbepoetin alfa they were receiving in the week preceding study start.