Anemia is common in patients with cancer or myelodysplastic syndrome. Erythropoietic therapy offers an effective way to manage anemia by increasing hemoglobin levels, decreasing transfusion requirements, and alleviating symptoms. We reviewed data showing the feasibility and effectiveness of treatment with the erythropoiesis-stimulating protein darbepoetin alfa at extended dosing intervals to treat anemia in patients with cancer receiving multicycle chemotherapy. We also explored the darbepoetin alfa's potential for treating anemia in patients with myelodysplastic syndrome. Data from clinical studies and drug therapy evaluations confirm that darbepoetin alfa administered weekly, every 2 weeks, and every 3 weeks corrects and maintains hemoglobin levels in patients with chemotherapy-induced anemia. In addition, the data demonstrate that both weight-based and fixed dosing with darbepoetin alfa are effective, and that early intervention to treat anemia has clinical benefits. Darbepoetin alfa also is an effective treatment for anemia in patients with cancer not receiving chemotherapy, at extended dosing intervals of at least 3 weeks. Extended dosing for anemia treatment can provide benefits for patients, caregivers, and clinicians because it reduces the number of clinic visits needed and permits synchronizing anemia treatment with chemotherapy cycles. Data from recent studies suggest that darbepoetin alfa is effective for treating anemia in patients with myelodysplastic syndrome; this potential use is being investigated further in ongoing studies. Thus, darbepoetin alfa is an attractive therapy option for patients with chemotherapy or cancer-induced anemia. It allows increased flexibility and simplified dosing and may offer some benefit in the treatment of anemia in patients with myelodysplastic syndrome.