Erythropoietin (EPO) is a hematopoietic growth hormone that regulates survival, proliferation, and differentiation of erythroid progenitor cells. A reduction in tissue oxygenation stimulates EPO production, through a complex feedback mechanism. Patients with cancer-related anemia have an inadequate EPO response that is further impaired by cancer treatments such as chemotherapy. Cancer-related anemia substantially impairs patient functioning and may contribute to poor treatment outcomes. A significant number of studies demonstrates that treatment of anemia in cancer patients using recombinant human EPO (rHuEPO, epoetin alfa) significantly increases haemoglobin (Hb) levels, reduces transfusion requirements, and improves quality of life, particularly by relieving fatigue. Recent data also show that epoetin alfa therapy may improve cognitive function in patients receiving chemotherapy. In addition, the correction of anemia may prolong survival by enhancing tumor oxygenation, thus increasing tumor sensitivity to chemotherapy or radiation. The indicated dose of epoetin alfa is 150-300 IU/kg three times per week, but it is commonly dosed at 40,000-60,000 IU once weekly based on trial data and extensive clinical use. Determining the timing of initiation of epoetin alfa is a clinical judgement; however, data suggest that patient functioning declines and the risk of transfusion increases when the Hb level falls under 12 g/dL.