A premenopausal simple hysterectomy is associated with a threefold increase in the subsequent incidence and prevalence of coronary heart disease during the remaining premenopausal years. During the 10 years following a premenopausal hysterectomy, there is an approximately 4% probability of developing coronary heart disease and a 0.4% probability of dying from it. For every 28 uterine cancer deaths prevented by hysterectomy in 30-year-old women, there is an operative death. To be assured that premenopausal hysterectomies do not cause more deaths from cardiovascular disease than they save by prevention of uterine cancer requires a prospective study of 20,000 women observed until death. Pending further elucidation of this phenomenon, gynecologists should consider advising premenopausal women considering hysterectomy on the risks of coronary heart disease following the procedure.