As patients who are Jehovah's Witnesses are against blood transfusion, they are difficult to manage when a cardiac intervention is required. Between 1998 and 2004, all Jehovah's Witness patients with an indication for cardiac surgery (n=10) were operated on by the same multidisciplinary team. The mean fall in hematocrit was 30% during cardiopulmonary bypass, 35% during the postoperative period, and 22% at discharge. One patient required cardiac re-exploration because of sternal bleeding. All patients survived operation and were discharged. At follow-up, 1 patient died due to respiratory failure. Technological developments that reduce bleeding and enable lost blood to be recovered have made it possible to perform operations involving a risk of hemorrhage in Jehovah's Witnesses.