This study will assess the efficacy and safety of intravenous (iv) or subcutaneous (sc) Mircera, administered with pre-filled syringes, as maintenance treatment for renal anemia in chronic kidney disease patients on dialysis who were previously receiving iv or sc epoetin. The anticipated time on study treatment is 3-12 months and the target sample size is 100-500 individuals.

Inclusion Criteria:

• adult patients >=18 years of age;
• chronic renal anemia;
• on dialysis therapy for at least 12 weeks before screening;
• receiving iv or sc epoetin for at least 8 weeks before screening.

Exclusion Criteria:

• women who are pregnant, breastfeeding or using unreliable birth control methods;
• administration of another investigational drug within 4 weeks before screening, or during the study period.