Five patients with sickle cell haemoglobinopathies underwent open heart surgery. At the start of the cardiopulmonary bypass the patient's circulating blood volume was separately drained into a bag, spun down and retransfused into the patient at the end of the operation. Moderate hypothermia, aortic cross clamping, topical hypothermia and cold crystalloid cardioplegia were used in all patients. None of the patients had transfusions in the postoperative period. No macroscopic or microscopic evidence of haemolysis were seen, nor haematuria or other clinical evidence of sickling. There was no evidence of wound infection and all were discharged home at a mean of 12.6 days. It is concluded that in cases of sickle cell anaemia exchange transfusion at the beginning of cardiopulmonary bypass followed by retransfusion of the red cell free blood can be used safely, permitting the performance of standard open heart procedures.