Chemotherapy can often cause anemia in patients with cancer. Anemia is a low number of red blood cells. The symptoms of anemia may include fatigue, dizziness, headache, chest pain, and shortness of breath. Erythropoietin is a hormone made by the kidneys that signals the bone marrow to produce more red blood cells. Recombinant human erythropoietin has been produced in the laboratory and has the same effect as the hormone produced by the body. Use of recombinant human erythropoietin allows the body to produce more red blood cells, possibly eliminating or decreasing your symptoms and the need for a red blood cell transfusion. Recombinant human erythropoietin is FDA approved to treat anemia in cancer patients receiving chemotherapy. This clinical study is investigating the effectiveness of darbepoetin alfa for the treatment of anemia in patients with non-myeloid malignancies who are receiving chemotherapy every three weeks. Darbepoetin alfa is a recombinant erythropoietic protein that stimulates the production of red blood cells. This medication has not been approved to treat cancer patients with anemia, however it has been approved by the FDA to treat chronic renal failure patients with anemia.