The present report is based on a review of the angiographic studies obtained in a series of 200 consecutive cases admitted to the Cerebral Vascular Service of Detroit Memorial Hospital with the clinical diagnosis of “stroke” or “cerebral vascular accident.” Every such case was studied by carotid or vertebral angiography or both. In the earlier cases only the side implicated by clinical and neurological findings was examined, but later, as more knowledge of the processes involved was gained, all cases were studied by bilateral carotid angiography and as many as possible by vertebral angiography as well. In all cases angiograms were obtained by percutaneous injection (both for carotid and vertebral studies) of 8 to 10 c.c. of 50 per cent Hypaque, in most cases under local anesthesia only. From two to as many as eight injections were given, with but one untoward reaction, an immediate fatality in a sixty-year-old woman who was critically ill with both cerebral vascular symptoms and severe paroxysmal hypertension. Autopsy in this case revealed a very unusual vascular neoplasm which almost completely occluded the main pulmonary artery and the proximal portions of its branches. That angiographic studies are quite safe in these cases is attested by the fact that many of the patients were critically ill, sometimes comatose or semicomatose, and often quite old and debilitated; yet they withstood the procedure without difficulty, with the single exception cited. It is not necessary at this time to describe the findings obtained on angiography in the numerous and varied pathologic entities which were responsible for the symptoms in this group of patients as indicated by the statistical analysis reported by Webster and Gurdjian elsewhere in this journal (p. 825), since these represent already familiar radiographic entities. The purpose of this report is rather to stress the radiologic manifestations of cerebral atherosclerosis, a subject which has received surprisingly little attention despite the vast literature on cerebral angiography. Some form of cerebral atherosclerosis was found to be the cause of stroke symptoms in 58 per cent of the cases studied. Complete Occlusion of Major Branches Internal Carotid Artery: The importance of complete occlusion of the internal carotid artery as a cause of “stroke” symptoms has been well documented (2, 4, 8). Such cases accounted for 10.5 per cent of this series. Most of these occlusions occurred immediately above the origin of the internal carotid artery in the neck (Fig. 1, A) although rarely the obstruction was seen more distally in the neck (Fig. 1, B) or even as high as the region of the carotid siphon. Demonstration of good filling of the external carotid branches usually obviates the need for a repeat injection to test the validity of the nonfilling of the internal carotid artery, especially if the needle point is in the common carotid artery below its bifurcation.