Erythropoietin is an effective treatment for anemia in patients with various types of cancers, but few studies have evaluated the benefit of treatment in advanced breast cancer. In this multicenter study, we investigated the influence of two different doses of epoetin-beta on the level of hemoglobin, the need for blood transfusion, quality of life and safety aspects in patients with metastatic breast cancer. A total of 180 patients were randomized to receive either 1000 IE or 5000 IE epoetin-beta subcutaneously three times per week for 24 weeks. An increase of 20 g/L was defined as a positive hemoglobin response. Blood transfusions were given, if clinically indicated. Additional laboratory values and adverse events were recorded. Quality of life was measured with the aid of the EORTC QLQ-C30 questionnaire. Hemoglobin levels increased significantly in both groups. In the high-dose group, the initial mean Hb value was 98 g/L (64-110), which increased to 121 g/L (83-165) by week 24. In the low-dose group, the mean Hb value was 99 g/L (77-110.5) and by week 24 it was 116 g/L (81-144). The majority of patients who responded to treatment did so during the first four weeks. After 4 weeks, 7 patients in the low-dose group and 24 patients in the high-dose group had increased their Hb values by more than 20 g/L. The need for transfusion was low and did not differ between the groups. Quality of life was significantly enhanced in both groups, and there was no difference in the global quality of life between the two study arms. Epoetin-beta is a well-tolerated, safe and effective treatment of anemia in patients with metastatic breast cancer. There were significant improvements in Hb levels and quality of life in both groups.