Hypertension constitutes a recognized risk factor of vascular dementia but also of Alzheimer-type dementia. Various longitudinal studies showed that midlife blood pressure level is one of the factors conditioning the onset of dementia syndrome in late life. The high risk of dementia is linked to leukoaraiosis, vascular rigidity, microcirculation disorders, oxidative stress, blood pressure fluctuations including orthostatic hypotension and strokes, all of those being associated with hypertension. Numerous clinical trials showed the positive effect of effective treatment of hypertension on the prevention of cognitive disorders and dementias. Thus, screening and early management of dementia and cognitive decline, in particular in the hypertensive subject, are essential. The Mini-Mental State Examination (MMSE) is a major first-intention screening test because it allows a full assessment of cognitive aptitudes. If cognitive decline is suspected and the MMSE score is considered to be abnormal, the elderly subject must be sent to a specialist or a referent memory centre; the MMSE is only a first stage in the diagnostic reasoning. MMSE should be included in the follow-up of all hypertensive elderly subjects and should be performed once a year by the general practitioner.