This 2 arm study will compare the effect on hemoglobin response of Mircera and epoetin beta, in patients with chronic renal anemia who are on dialysis. Eligible patients will be randomized to receive either Mircera (0.4 micrograms/kg i.v. every 2 weeks) or epoetin beta (3 times weekly, according to approved labelling). 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 requiring dialysis;
• maintenance hemodialysis or peritoneal dialysis for >=2 weeks before and during screening;
• adequate iron status.

Exclusion Criteria:

• previous epoetin treatment within 8 weeks prior to screening;
• failing renal graft in place;
• bleeding episode necessitating transfusion within 8 weeks prior to screening;
• poorly controlled hypertension;
• previous treatment with Mircera.