Preoperative anemia is associated with increased postoperative morbidity and mortality and with increased risk of perioperative transfusion. It is an important and modifiable risk factor for surgical patients. For high-blood-loss surgery, preoperative anemia is defined as hemoglobin <13 g/dL for both male and female patients. Preoperative anemia is common, ranging from 25% to 40% in large observational studies. The most common treatable cause of preoperative anemia is iron-deficiency anemia; the initial laboratory tests should focus on making this diagnosis. Management of iron-deficiency anemia includes iron supplementation with IV iron therapy when oral iron is ineffective or not tolerated, there is severe anemia, and there is insufficient time to surgery (<4 weeks). In other situations, erythropoiesis-stimulating agents may be considered, particularly for those patients with multiple alloantibodies or religious objections to transfusion. To facilitate the diagnosis and management of preoperative anemia, establishment of preoperative anemia-screening clinics is essential. The goals of management of preoperative anemia are to treat anemia, reduce the need for transfusion, and improve patient outcomes.