Anemia is a common and potentially debilitating complication of cancer. Darbepoetin alfa (Aranesp, Amgen) has been in routine clinical use for the treatment of chemotherapy-induced anemia since 2002. The extended half-life of darbepoetin alfa permits less frequent and consequently more flexible dosing than other erythropoietic therapies. Data suggest that hemoglobin levels can be effectively and safely increased with darbepoetin alfa in cancer patients who are receiving chemotherapy (patients with treatment-induced anemia), and in those who are not receiving chemotherapy (patients with tumor-induced anemia). This review provides an overview of clinical trial results, particularly those exploring flexible, extended dosing schedules.