To evaluate the safety and effectiveness of the intraoperative phlebotomy with acute hemodilution and autologous transfusion as an approach to blood conservation during cardiac operation, 126 patients were grouped into autologous transfusion group(Group I, n=54), prospective control group(Group II, n=22), and retrospective control group(Group III, n=50). Intraoperative hemodilution was practiced in autologous transfusion group before extracorporeal circulation. After an extracorporeal circulation, the units of blood phlebotomized were transfused. Hematocrit, platelet count, PT(prothrombin time), PTT(partialthromboplastin time), MAP(mean arterial pressure), and amount of homologous transfusion were measured immediately after induction, during bypass, and at the intensive care unit. Blood loss was measured at 12 hours and 24 hours after arrival at intensive care unit. Incidence of hemologous transfusion was 62% in group I, 86.4% in group II, and 100% in group III. Patients received 2.2±0.4 units in group I, 4.1±0.8 units in group II and 6.7±0.5 units in group III. Coagulation studies showed no significant improvement in autologous transfusion group who received fresh autologous blood. There was no difference in blood loss postoperatively among 3 groupes. In conclusion, our data suggest that the use of autologous transfusion with hemodilution reduces usage of homologous blood in all cardiac surgery procedures.