A successful program to reduce the amount of blood required in cardiac surgical procedures should encompass all phases of surgical therapy: preoperative exclusion or treatment of coagulation disturbances, intraoperative hemodilution to a hematocrit of 20% and subsequent reinfusion of autologous blood, and postoperative reinfusion of shed mediastinal blood during the first 12 postoperative hours keeping the hematocrit at 28%. In 1977, the bank blood requirement for 527 cardiac surgical procedures (control group) averaged 2 units per patient. Twenty-seven percent could be operated on without bank blood. Intraoperative hemodilution was applied lowering the hematocrit to 23%. The postoperative limit for blood transfusion was a hemoglobin of 11 g/100 ml or a hematocrit of 32%. The reinfusion of shed mediastinal blood, introduced in 1978 (512 patients), has reduced the need for bank blood by 50% to one unit per patient (p less than 0.001). Fifty-three percent of the patients required no bank blood. Since mid-1980 (350 patients), postoperative hemodilution has reduced the need for bank blood to 0.3 units per patient (p less than 0.001). Eighty percent of the operations could be carried out without bank blood. The postoperative blood loss of 1.4 units per patient was identical in both the control and reinfusion groups. This reduction of homologous blood transfusions results in a decreased risk of hepatitis for the patient and in a financial advantage for the hospital.