Previous studies have demonstrated that cerebral blood flow (CBF) can be assessed noninvasively by MRI using magnetic labeling of arterial water as a diffusible flow tracer. The purpose of this study was to assess the quality of CBF images obtained from patients with cerebrovascular disease using this method, and to begin to evaluate the potential clinical role for this technique. We recruited 14 patients who presented with stroke, TIA, or severe carotid stenosis and were likely to have altered CBF based on clinical assessment. In many of these patients, CBF imaging disclosed both focal and hemispheric hypoperfusion, either in vascular territories or in watershed regions. In 11 patients with significant proximal arterial stenosis, hemispheric CBF abnormalities localized to the side of most significant stenosis for the anterior circulation distribution. In several patients watershed hypoperfusion was even more pronounced. Our results suggest that good-quality MR CBF images can be obtained reliably from patients with cerebrovascular disease. CBF imaging can be combined with standard structural imaging within a single MRI examination, and provides clinically meaningful information. The capability of measuring CBF easily provides a potentially useful tool for clinical assessment and further investigation of stroke pathophysiology.