The menopause is associated with a relatively abrupt decline in the ovarian production of estrogen that results in a state of estrogen deficiency. This estrogen deficiency state is associated with an accelerated expression of cardiovascular disease, osteoporosis, urogenital atrophy, dermal aging, an increased expression of colorectal cancer, an alteration in the expression of breast cancer that results in more malignant forms of the disease, and the loss of neurons from the brain that is associated with a more rapid decline in cognitive function, balance, and an earlier expression of Alzheimer's disease. Macular degeneration and cataract formation may be additional consequences of the estrogen deficiency state. Thus the estrogen deficiency state may be characterized as a state of accelerated aging. The abrupt transition from the reproductive state of multiple estrogen-dependent neural systems within the brain may affect their function as manifested by the typical menopausal symptoms of hot flashes, mood changes, sleep disturbance, and cognitive impairment. This transition may trigger a cascade of events that contributes to the acceleration of brain aging and the expression of neurodegenerative processes as Alzheimer's disease. This article discusses the use of estrogen to prevent these age-related changes.