Anemia has been identified as a common complication and a widespread problem in the cancer population. Anemia is a condition in which a patient has below normal levels of hemoglobin, the substance in red blood cells that carries oxygen to all parts of the body. People with severe anemia may experience fatigue and shortness of breath with activity. Therefore, this condition can have a negative influence on a person's quality of life. Epoetin alfa, used to treat anemia in cancer patients, is a genetically engineered protein that stimulates red blood cell production. This study investigates treatment of anemia using epoetin alfa during chemotherapy in adult patients with cancer. The study is intended to collect information on normal medical practice and routine anemia management performed at the participating centers. This is an observational, non-randomized, prospective, comparative, parallel-group survey performed in The Netherlands. Patients with various severities of disease may enter the survey as soon as their epoetin alfa treatment starts and will be followed until the end of their epoetin alfa treatment. Patient data are collected in Case Report Forms (CRFs) until 4 weeks after the end of treatment with epoetin alfa. At the end of treatment completed CRFs will be collected. The assessment of effectiveness/response will be based on the following: cancer type and status, chemotherapy and other anti-cancer treatment, hemoglobin levels, use of blood transfusions, and serum iron levels and iron supplementation. Safety evaluations include the incidence of serious and non-serious adverse events. Because the study is observational, dosage, administration and duration of treatment is at discretion of treating physician.