With oophorectomy, the physiologic changes associated with menopause occur quickly and with a significant impact on a woman's quality of life. In naturally menopausal women, ovarian hormone biosynthesis provides low circulating levels of estrogen and androgen. In the surgically menopausal woman, estrogen and androgen levels are significantly reduced. In surgically menopausal women for whom supplemental estrogen is prescribed, sex hormone binding globulin levels increase dramatically, resulting in reduced bioavailability of the remaining estrogens and androgens that result from peripheral conversion. This paper reviews the physiologic changes associated with natural and surgical menopause and the effects of estrogens and androgens at the cellular level. It describes the effects of hormone replacement on endogenous hormones and on the symptoms of menopause that result from physiologic changes, including vasomotor instability, sexual dysfunction and urinary complications. It also addresses the effects of estrogen/androgen therapy on physiologic symptoms.