We present a selected series of nine patients with unclippable internal carotid artery aneurysms to illustrate our current approach to this problem. Eight of the nine underwent common carotid ligation after preoperative angiographic evaluation. Tolerance to carotid occlusion was determined intraoperatively by awake examination, electroencephalogram (EEG) monitoring, and carotid stump pressure measurements. No patient developed a permanent deficit; seven of eight treated aneurysms have thrombosed. Our experience and review of the literature indicate that most ischemic complications after carotid ligation seem to be thromboembolic, rather than due to "low flow" from poor collateral circulation. For this reason, we have gradually come to favor common carotid (CCA) over internal carotid (ICA) occlusion in many of these patients. After CCA occlusion, the ICA frequently remains open and embolic complications are therefore less likely. An extracranial-intracranial bypass procedure is performed only in those patients with poor collateral circulation demonstrated by cross compression angiographic studies, by the development of new deficits during test occlusion, or by the appearance of EEG changes during test occlusion. We suggest that CCA ligation remains a useful alternative in the management of unclippable internal carotid aneurysms.