Abstract—Cerebrovascular disease and Alzheimer disease are common diseases of aging and frequently coexist in the same brain. Accumulating evidence suggests that the presence of brain infarction, including silent infarction, influences the course of Alzheimer disease. Conversely, there is evidence that -amyloid can impair blood vessel function. Vascular -amyloid deposition, also known as cerebral amyloid angiopathy, is associated with vascular dysfunction in animal and human studies. Alzheimer disease is associated with morphological changes in capillary networks, and soluble -amyloid produces abnormal vascular responses to physiological and pharmacological stimuli. In this review, we discuss current evidence linking -amyloid metabolism with vascular function and morphological changes in animals and humans.