The immediate postoperative cerebral complications of 65 carotid occlusions were evaluated. The occlusions were done in all but one case for intracranial saccular aneurysms and were performed by either direct ligation (quick type) or slow turning down of a Silverstone clamp or similar device (slow occlusion). Cerebral complications occurred in 21 patients. The quick type of occlusion of the artery resulted in a complication rate of 24% whereas the slow type had a rate of 38%. A total of 123 cases involving cerebral complications after carotid ligation were collected from the literature and evaluated. The combined total of 81 cases of transient complications that were collected from the literature and from our series showed that such deficits occur frequently from 10 minutes to six hours after the occlusion of the vessel.