There is a long history of hormones altering behavior and endocrinopathies playing a role in psychiatric disease. This article highlights the hormonal changes that occur with aging and the effects of these hormonal changes on the brain, concentrating not on the well-known psychiatric manifestations of endocrine diseases, but on the more subtle effects of hormones and metabolic alteration seen in many older persons. The article focuses predominately on the role of hormones in cognition, as dementia and mild cognitive impairment are major problems in the older individual.