Alzheimer's disease, cerebrovascular disease and aging-related cognitive impairment and dementia (ARCID) increase in prevalence in women with advancing age. The development of Alzheimer's disease, cerebrovascular disease and ARCID may be postponed or prevented by protective measures including the active treatment of vascular risk factors and continuing exercise and healthy lifestyle from early-and mid-life onward. Bilateral oophorectomy before the natural menopause is associated with an increased incidence of ARCID and the increased risk is significantly reduced by estrogen therapy. Recent advances in menopause hormone therapy including transdermal estrogen therapy have favorably influenced the balance of benefits and risks. A case can be made for menopause hormone therapy in healthy postmenopausal women for 5-10 years starting during the menopausal transition (the `window of opportunity'), together with all other protective measures, to delay or prevent the development of ARCID in later life.