We studied 90 consecutive cases undergoing open heart surgery with preoperative collection of autologous blood and ultrafiltration during extracorporeal circulation. Among the 58 out of 90 patients (64.4%), open heart surgeries were achieved without homologous blood. We evaluated 13 factors (age, height, weight, body surface area, cardiopulmonary bypass time, aortic cross clamping time, dilutional rate, Hct before predonation, lowest Hct during cardiopulmonary bypass, amount of predonated autologous blood, term of autologous blood predonation, amount of bleeding during surgery, amount of bleeding after surgery) in connection with open heart surgery without homologous blood. Among these factors, age, body surface area, cardiopulmonary bypass time, aortic cross clamping time, lowest Hct during cardiopulmonary bypass, amount of predonated autologous blood, amount of bleeding during surgery and amount of bleeding after surgery demonstrated differed significantly between the only autologous blood transfusion group and the homologous blood transfusion group. According to the evaluation by multivariate regression analysis of these factors, the amount of bleeding after surgery was the most contributor to open heart surgery without homologous blood, followed by amount of bleeding during surgery and body surface area. We concluded that open heart surgery without homologous blood may be achieved in more patients by understanding these factors. Autologous blood predonation by the “leapfrog” method, control of the dilution rate by ultrafiltration during extracorporeal circulation and fresh autologous blood transfusion after extracorporeal circulation were effective to achieve open heart surgery without homologous blood.