Estrogen replacement therapy is the most effective single means of preventing and treating osteoporosis. The most common objection by patients, the resumption of menses if the uterus is present, may be eliminated by providing estrogen and progestin continuously. An additional concern, endometrial carcinoma, appears to be largely alleviated by coadministration of progestin. Evidence indicates that concomitant progestin administration actually reduces the incidence of endometrial carcinoma to less than that in untreated women. An incidental but potentially more important benefit is protection against coronary artery disease. Optimal management includes initiation of estrogen therapy shortly after menopause, long-term continuation and calcium supplementation.