Patients with aortic arch aneurysms underwent surgery using a selective cerebral perfusion (SCP) method. For this purpose, a protocol for SCP was established on the basis of an animal experimental study. Our SCP procedure is performed at a perfusion rate of 6 ml/kg/min with the patient under deep hypothermia at 20 degrees C. The subject group in the current study included 36 patients, 28 men and eight women, ranging in age from 23 to 84 years (mean, 61). There were five operative deaths (13.9%). The mean cardiopulmonary bypass time was 288 minutes, and the mean aortic clamp time was 135 minutes. Mean SCP time was 89 minutes, exceeding 90 minutes in 17 cases. The mean blood pressure during SCP was 43 mmHg and oxygen saturation rate in the internal jugular vein was at least 90%. There was no definite production of lactate in the brain. Cerebral disorders considered to have been caused by SCP occurred in only two cases. It appears that cerebral metabolism can be maintained safely, and that our SCP method is useful during surgery for aortic arch aneurysms.