Under normal physiologic conditions the level of circulating red blood cells is regulated precisely by the glycoprotein erythropoietin. In major elective surgery, patients who are participating in preoperative autologous blood donation or who are anemic may not have the capacity to manufacture sufficient red blood cells in response to increases in endogenous erythropoietin that is sufficient to avoid perioperative allogeneic blood transfusion. In these patients pharmacologic doses of recombinant human erythropoietin (Epoetin alfa) have been shown to accelerate erythropoiesis, thereby increasing preoperative red blood cell production, hematocrit level, and hemoglobin concentration and reducing exposure to allogeneic blood transfusion. In four large multicenter studies, 869 patients undergoing major elective surgery were treated with a daily regimen (300 or 100 IU/kg x 14 or 15 doses) or a weekly regimen (600 IU/kg x 4 doses) of subcutaneous Epoetin alfa beginning either 2 or 3 weeks before surgery, respectively. Although all Epoetin alfa regimens were effective at accelerating erythropoiesis and increasing red blood cell production, the weekly regimen was the most patient friendly, cost effective regimen for treating preoperative anemia and minimizing patient risk of allogeneic blood transfusion.