Patients undergoing major orthopedic surgery frequently require blood transfusions both during and after the operation. Agents that can increase the rate of red blood cell production would reduce the need for blood transfusions. Epoetin alfa is a genetically engineered form of a natural hormone, erythropoietin, that stimulates red blood cell production. This is a randomized, double-blind, placebo-controlled, parallel group, multicenter study. The study compares the effectiveness of epoetin alfa in reducing the need for blood transfusions in patients who are expected to require at least 2 units of blood following major orthopedic surgery. Eligible patients will be randomly assigned to receive either epoetin alfa (100 or 300 U/kg, depending upon their body weight) or a matching placebo, by injection beneath the skin starting 10 days before scheduled surgery, on the day of surgery (after surgery), and for 4 days after surgery. Additionally, all patients will start taking an oral iron supplement at least 10 days before their scheduled surgery. Effectiveness will be determined by the number of transfusions required following surgery, and on changes in hematocrit (iron-containing pigment in red blood cells), hemoglobin (oxygen-carrying component of red blood cells), and reticulocyte (immature red blood cells) levels from the start of the study to the end of the study. Safety evaluations will include the incidence and severity of adverse events, and changes in clinical laboratory tests, vital signs, and physical examination findings throughout the study. The study hypothesis is that patients treated with epoetin alfa will require fewer blood transfusions after surgery than patients treated with placebo. Epoetin alfa (300 U/kg or 100 U/kg), or matching placebo, by injection beneath the skin beginning 10 days before scheduled surgery and ending 4 days after surgery.