Abstract Vascular disease is one of the major concerns of clinical neuroscience and medicine. Stroke continues to be the third leading cause of death in the United States, and represents an enormous source of disability from neurologic and neurobehavioral dysfunction. Many controversies persist in the area of vascular disease, but one that has captured much recent attention concerns the importance of the white matter. A lively debate in neurology has centered on the origin and significance of white matter changes that are frequently seen on the neuroimaging scans of older individuals. These findings have prompted a renewed examination of the concept of vascular dementia, which continues to undergo revision. In this chapter, a number of clinical entities in which white matter vascular disease occurs are reviewed, with particular attention to the neurobehavioral implications of these lesions.