• Change in Hb concentration between reference and evaluation period [ Time Frame: Week 17-24 ] [ Designated as safety issue: No ]
• Mean time spent in country-specific target range; percentage of patients maintaining Hb within target range; dose adjustments; RBC transfusions. [ Time Frame: Throughout study ] [ Designated as safety issue: No ]
• AEs, laboratory parameters, vital signs [ Time Frame: Throughout study ] [ Designated as safety issue: No ]

This single arm study will assess the long-term maintenance of hemoglobin levels, safety and tolerability of once-monthly intravenous administration of Mircera in hemodialysis patients with chronic renal anemia. Patients currently receiving darbepoetin alfa, epoetin alfa or epoetin beta maintenance treatment will receive intravenous Mircera at a starting dose of 120 or 200 micrograms/month (based on the ESA dose administered on week -1). Subsequent doses will be adjusted to maintain hemoglobin levels within the country-specific target range (11-13g/dL for Switzerland and 10-12g/dL for Austria). The anticipated time on study treatment is 1-2 years, and the target sample size is 100-500 individuals.

Inclusion Criteria:

• adult patients, >=18 years of age;
• chronic renal anemia;
• Hb conc. in country-specific target range (Switzerland: 11g/dL-13g/dL; Austria: 10g/dL-12g/dL);
• regular long-term hemodialysis therapy with the same mode of dialysis for >=3 months;
• continuous iv or sc maintenance ESA treatment during previous 2 months.

Exclusion Criteria:

• transfusion of red blood cells during previous 2 months;
• significant acute or chronic bleeding, such as overt gastrointestinal bleeding;
• active malignant disease (except non-melanoma skin cancer).