Carotid bifurcation aneurysms have, as a group, certain characteristics. They account for about 7% of all intracranial aneurysms. They appear to be mostly leftsided and there does not seem to be any particular sex predominance. When associated with other aneurysms, the carotid bifurcation aneurysm was the symptomatic lesion. Demonstration of small aneurysms may be difficult and accurate definition of the neck may not be possible at angiography. They appear to associate themselves with one or the other division of the internal carotid artery. With careful exposure and appropriate positioning of the head it is possible to occlude these aneurysms with a clip, but we feel that the inexperienced surgeon should not tackle these cases. Carotid artery ligation may not prevent rebleeding in this group of aneurysms.