The prevalence of hypertension is estimated to approach 50% in individuals above age 70. The consequences of hypertension include cerebrovascular disease, coronary heart disease, and general atherosclerosis. Several recent studies suggest that there may be an association also between hypertension and Alzheimer's disease (AD). This review will examine the evidence for this association and possible pathways between hypertension, Alzheimer encephalopathy, and clinical dementia.