Approximately 78% of women between the ages of 45 and 64 years have prophylactic oophorectomy when hysterectomy is performed for benign disease to prevent the development of ovarian cancer. However, after menopause, the ovary continues to produce androstenedione and testosterone in significant amounts and these androgens are converted in fat, muscle, and skin into estrone. Evidence suggests that oophorectomy increases the subsequent risk of coronary heart disease (CHD) and osteoporosis and whereas 14,000 women die of ovarian cancer every year nearly 490,000 women die of heart disease and 48,000 women die within 1 year after hip fracture. PubMed and the Cochrane database were used to identify studies that examined the incidence of disease and mortality from 5 conditions that seem to be related to ovarian hormones: CHD, ovarian cancer, breast cancer, stroke and hip fracture, and also data for death from all other causes. The data were applied to a Markov decision analytic computer model to calculate risk estimates for mortality from these conditions until the age of 80. The model shows for a hypothetical cohort of 10,000 women undergoing hysterectomy and who chose oophorectomy (vs. ovarian conservation) between the ages of 50 and 54 [without estrogen therapy(ET)], that by the time they reach age 80, 47 fewer women will have died from ovarian cancer, but 838 more women will have died from CHD and 158 more will have died from hip fracture. Therefore, the decision to perform prophylactic oophorectomy should be approached with great caution for the majority of women who are at low risk of developing ovarian cancer.