All available estimations agree that the French population is aging and that the proportion of diabetics in the elderly population is increasing. The prevalence of diabetes could be about 10% in the over 65 y population. The fact that diabetes has an effect on brain function is widely accepted, but there are very few studies providing pertinent details. Diabetes is known to affect brain function, potential consequences including cognitive decline, dementia, depression, and stroke. These complications are frequently associated, leading to poor quality-of-life with considerable social and economic impact. While the results of different studies can be contradictory, there is an overall trend towards the conclusion that diabetes, often associated with high blood pressure, contributes to cognitive decline in elderly diabetics as well as to an increased frequency and severity of cerebral vascular events. These considerations point out the importance of proper management of diabetes in the elderly population and the need for cooperative studies to determine the role of diabetes and different cardiovascular risk factors in the development of dementia, stroke, and depressive syndromes whose consequences are probably underestimated.