Essential hypertension has rather recently become recognized as a major factor in the development of the 2 main types of dementia, that is, no longer merely vascular dementia but Alzheimer disease as well. The relationship between high blood pressure (BP) and the dementias is quite a complicated one, given a wide variability in temporal courses. The interval between the respective manifestations of hypertension and cognitive deterioration may vary from a few years to several decades. Moreover, temporal relationships may be obscured because of the observation that BP tends to fall in the face of imminent Alzheimer disease. Although the cause-and-effect sequence of this relationship has not been established, it may suggest that a low BP in this phase of life could be equally harmful as hypertension in the preceding period. Individual monitoring of BP and drug titration in the hypertensive elderly may well become mandatory in the highest age group. The question whether some antihypertensive drug categories might act more effectively in preventing cognitive deterioration than others, irrespective of their antihypertensive potential, remains. A modest meta-analysis on our part seems to suggest that suppression of the renin-angiotensin-aldosterone system (RAAS) would fail to offer such protection, in contrast to certain dihydropyridine (DHP) calcium-channel blockers. Unfortunately, recently published comparative prospective megatrials (Anti-hypertensive and Lipid-lowering Treatment to Prevent Heart Attack Trial and Anglo-Scandinavian Cardiac Outcomes Trial-Blood Pressure Lowering Arm) failed to carry any record on the mental status of the study populations, thereby missing a golden opportunity to resolve the above issue. Consequently, there remains an urgent need for further blinded long-term comparative hypertension trials, including follow-up evaluation of cognitive functions in relation to the course of BP.