The EC/IC bypass is being performed more and more, and angiography is essential as part of the postoperative evaluation. This review of 41 patients points out the need for selective external carotid angiography in those cases where intracranial vessels fill spontaneously at the same time as the shunt. However, 8 of 11 cases showed the superficial temporal artery to be larger on the selective external carotid angiogram than in the common carotid study done during the same session. In two cases undergoing staged occlusive procedures as treatment for giant aneurysm, the external carotid artery leading to an EC/IC was occluded as an angiographic complication without neurologic sequelae.