An increase in ovarian steroid secretion could play a role in the pathogenesis of endometrial cancer in postmenopausal women. The present study was undertaken to investigate steroid production by isolated ovarian stromal tissues of postmenopausal women with endometrial cancer and to study the effect of LH and insulin on ovarian steroidogenesis in postmenopausal women. Ovarian stromal tissue was obtained from 10 postmenopausal women with endometrial cancer and 8 women without cancer. The stroma was incubated in either the medium alone or the medium to which was added LH (50 ng/mL) or insulin (500 ng/mL). The ovarian stroma of postmenopausal women with cancer released significantly more androstenedione (A), testosterone, and dehydroepiandrosterone than that of women without cancer. Addition of LH resulted in a significant increase in A, testosterone, dehydroepiandrosterone, and progesterone release compared to that with vehicle alone. Addition of insulin stimulated the release of A from the ovarian stroma of women with cancer, but had no effect on the normal postmenopausal ovarian stroma. These results indicate that the ovarian stroma of postmenopausal women with endometrial cancer secrete significantly greater amounts of androgens than those of women without cancer and that both LH and insulin may be important factors contributing to this increase in ovarian steroidogenesis.