Extracorporeal circulation in the treatment of aneurysms of the ascending aorta and transverse arch present both the surgeon and perfusionist with a formidable challenge. Thirty-one patients presented with either of these anomalies and have been treated in a two-year period from August 1987 to December 1989 at the University of Michigan. Of these, 11 had lesions which involved one or more arch vessels and necessitated either a period of circulatory arrest (7 patients) or brachiocephalic perfusion (four patients). Mean circulatory arrest periods were 44.8 ± 9.0 minutes (Mean ± SD), while the brachiocephalic perfusion patients had one or more arch vessels cannulated for a mean length of 64.3 ± 19.7 minutes. Postoperative complications in both groups included pulmonary and renal insufficiency, coagulopathies, and neurological deficits. The circulatory arrest group experienced encephalopathies (5/7 patients) and high perioperative mortality (4/7 patients). In the brachiocephalic perfusion group only one patient experienced postoperative neurological complications and there were no immediate postoperative deaths. Lesions of the ascending and transverse aorta are often associated with high morbidity and mortality. Although these population groups are small we believe that the technique of cerebral perfusion via cannulation of the brachiocephalic vessels provides a safe alternative to that of hypothermic circulatory arrest.