Episodic memory is affected by cognitive ageing, and memory impairment beyond that expected on the basis of usual ageing may be an early indicator of Alzheimer's disease. Although memory complaints are common in midlife, it is reassuring that the natural menopausal transition is unaccompanied by objective memory loss. Less is known about memory after surgical menopause. Estrogen-containing hormone therapy initiated during the late postmenopause increases dementia risk and does not improve memory. It is unclear whether hormone use during the menopausal transition or early postmenopause affects Alzheimer risk. Observational studies imply a protective association consistent with the so-called critical window hypothesis, but these findings could be biased. Clinical practice implications are presented.