Anemia is a decrease in circulating red blood cells that contributes to a complex group of symptoms. Anemia may be present in more than half of all patients with cancer but often is assessed, documented, prevented, and treated inadequately. Individuals with cancer are living longer, and the number of cancer treatment options provided at various points in the cancer continuum is growing; however, many treatments contribute to anemia. Because anemia can develop from multiple causes, treatment must be tailored to the underlying etiology. Cancer-related anemia can significantly affect therapeutic outcomes and patients' quality of life. Therapeutic interventions may include blood transfusions, administration of recombinant human erythropoietin, and interventions to support patient symptoms, most significantly, fatigue. Oncology nurses play a central role in risk assessment, symptom management, treatment planning, and evaluation and therefore must understand the etiology and physiology of cancer-related anemic states as well as evidence-based interventions to ensure optimal outcomes.