Oophorectomia per occasionem is often performed in connection with hysterectomy in peri- and postmenopausal women as prophylaxis against ovarian cancer. Reviewing published articles has shed little light on whether the postmenopausal ovaries have an endocrine function, and whether such a function may have physiological importance. Population studies of healthy women, comparisons of oophorectomized and non-oophorectomized postmenopausal women and measurements of ovarian venous gradients have shown that the postmenopausal ovaries contribute substantially to the production of androgens, and produce about half the body's circulating testosterone. In a number of women there is a continued significant oestrogen production in the ovaries during the first five to ten years following menopause. After this period the ovarian contribution to the total oestrogen production is very small. To what extent the continued androgen production could have physiological importance cannot be decided by reviewing the literature. Androgens seem to have importance for sexual function, but could possibly also have negative effects in the form of an increased risk of cardiovascular disease. We lack both epidemiological investigations and in-vitro perfusion studies of human ovaries in order to illuminate the physiological function of the postmenopausal ovary. In deciding on oophorectomia per occasionem in the postmenopausal woman the possible advantages of continued ovarian hormonal production must be weighed against the risk of later development of ovarian cancer, which is 2%, identical to that of the risk in the background population.