Dementia, which dramatically increased in recent years is one of the most important issues in the modern society. Solutions for prevention and management of dementia have not been established. Since hypertension status in middle-age period is known as a risk for the future development of dementia, antihypertensive treatment during such period is important. On the contrary, the influence on the dementia development of hypertension during old-age period has not been clarified yet. Since some reports showed that the antihypertensive treatment prevented the development of dementia, the proper antihypertensive treatment would be considered. It is still unknown that of which kind of antihypertensive drug is most effective for preventing dementia, since clinical trials have not been performed on such hypothesis to be solved. Recent report on the network meta-analysis showed that angiotensin receptor blockers were most effective. Future study should be done for develop the evidence for preventing dementia as a primary endpoint.