Anemia is commonly encountered in the preoperative patient. Determination of the cause of the anemia can affect perioperative surgical and medical management and outcome. Red blood cell transfusions are often administered during the perioperative time period in patients with preoperative anemia, although evidence to support the optimal transfusion threshold is limited. The authors review the evaluation of anemia and evidence regarding perioperative blood transfusions. Recommendations on the treatment of anemia, including perioperative blood transfusions, are outlined.