Anemia signifies an underlying disease and is associated with poor clinical outcomes. In elderly patients, in whom anemia has a high prevalence (greater than 10 percent), neither the hemoglobin threshold for concern nor the identity of the anemia-causing disease is easily established. This is an important shortfall, because even mild anemia can compromise patient well-being and survival, regardless of the underlying cause. This review discusses definitions of "normal" hemoglobin levels in adults, common causes of anemia in people aged 65 years and older (eg, nutritional deficiency, renal insufficiency, inflammatory disorders, and myelodysplastic syndrome), and potential consequences of anemia in elderly patients (eg, poorer cognitive status, increased frailty, and an elevated risk of hospitalization and of complications during hospitalization). We also outline a practical initial diagnostic approach that helps determine appropriate treatment, and we weigh therapeutic options in light of new safety concerns regarding erythropoiesis-stimulating agents.