Essential hypertension has devastating effects on the brain, being the major cause of stroke and a leading cause of dementia. Hypertension alters the structure of cerebral blood vessels and disrupts intricate vasoregulatory mechanisms that assure an adequate blood supply to the brain. These alterations threaten the cerebral blood supply and increase the susceptibility of the brain to ischemic injury as well as Alzheimer's disease. This review focuses on the mechanisms by which hypertension disrupts cerebral blood vessels, highlighting recent advances and outstanding issues.