It is now possible to evaluate regional cerebral hemodynamics in patients with atherosclerotic occlusive cerebrovascular disease using noninvasive techniques to study the cerebral circulation and metabolism. The degree of carotid stenosis and the presence of carotid occlusion correlates poorly with the hemodynamic status of the ipsilateral cerebral circulation due to the variation of the collateral cerebral circulation in individual patients. Atherosclerotic occlusive cerebrovascular disease is a complex multifactorial disease, and the role of cerebral hemodynamics in the pathophysiology of patients with ischemic cerebrovascular disease is not entirely clear. Further studies of cerebral hemodynamics and metabolism are needed to determine whether or not this is an important factor in the therapy and prognosis of patients with atherosclerotic occlusive cerebrovascular disease.