1. Menopause, defined as the permanent cessation of menstruation resulting from loss of cyclic ovarian function, occurs spontaneously at a mean age of 51 years. More than 40 million American women are postmenopausal, and an additional 30 million are expected to join their ranks during the next decade. 2. The depletion of naturally occurring hormones that accompanies menopause and the issue of hormone replacement therapy have become fundamental concerns in women's health care. 3. Many experts now advise estrogen-progestin replacement therapy to prevent osteoporosis in all women at high risk for this disorder, and for vasomotor flushes, genitourinary symptoms, and mood changes in women who have no contraindication to this therapy. 4. Hormone replacement therapy plays a pivotal role in preserving good health and vitality, but it should be presented within the context of other health-promoting measures to be adopted by menopausal and postmenopausal women.