An increasing number of patients with symptomatic carotid artery occlusion are being referred for extracranial to intracranial bypass grafts. After careful clinical and angiographic assessment, a number of these patients have been treated with a direct approach to the carotid arteries in the neck or with anticoagulation rather than with a bypass graft. These patients may be categorized diagnostically under the following heading: 1) complete occlusion of the internal carotid artery (ICA) with intracranial patency; 2) spontaneous dissection of the ICA: 3) atheromatous pseudo-occlusion; 4) carotid artery occlusion with stenosis of the contralateral ICA; 5) occlusion of the ICA and stenosis of the external carotid artery; and 6) thrombus in the intracranial segment of an occluded ICA. Each of these categories is discussed briefly, and illustrative cases are presented.