Obesity and dementia, which prevelance of them are increasing day by day, are serious health problems. In recent years, the studies which are examining the relationship between obesity and dementia has increased. It is known that obesity effects on chronic diseases such as diabetes mellitus, cardiovascular disease, cancer, however, the results of studies examining the effect on dementia are inconsistent in the literature. Studies focused on dementia which is the most common Alzheimer's type. Although the mechanism between obesity and dementia evaluated in many ways, a definite conclusion hasnt been reached. It is considered that it is needed to carry out follow-up and longitudinal studies for the evalution of this relationship.