Anemia commonly occurs in patients with cancer or human immunodeficiency virus (HIV) infection as a result of the disease, its treatment, or both. The negative impact of anemia on patient quality of life (QOL), functional status, and treatment outcomes underscores the need for its correction in these patients. In anemic patients with cancer or HIV infection, treatment with epoetin alfa increases hemoglobin (Hb) levels, decreases transfusion requirements, and improves QOL. In both settings, the gains in overall QOL have been significantly and directly related to increases in Hb, with maximum QOL gains in the range of Hb levels of 11-13 g/dL, supporting the need to achieve and maintain Hb levels greater than or equal to12 g/dL in an effort to preserve and maximize QOL benefits. A potential survival benefit has also been associated with correction of anemia in patients with HIV infection-and possibly in those with cancer as well.