Multiple epidemiological and brain imaging studies show a strong association between elevations in systolic blood pressure and lesions of cerebral white matter. The association between white-matter lesions and systolic blood pressure persists even if individuals are receiving treatment, suggesting that these individuals may be undertreated. In addition, these studies suggest that lesions of cerebral white matter may serve as markers for atherosclerotic vascular disease. Treatment strategies, therefore, should focus on early and aggressive management of elevated blood pressure, but definitions of elevated blood pressure may need to be revised downward to achieve best results.