The effects of estrogenic steroid hormones in women are apparent, but the circulating androgen levels are much higher. Compared with serum estrone and estradiol levels, circulating testosterone levels are five to 10 times higher, androstenedione levels 30 times higher, dehydroepiandrosterone levels 100 times higher, and dehydroepiandrosterone sulfate levels 40,000 times higher. Androgen production in women is physiologically appropriate, but it differs from other hormonal systems in that there seem to be no mechanisms controlling the serum levels. Androgens are produced almost incidentally from reproductive and ACTH-adrenal axes. No distinct feedback systems have been identified for the androgens, although the lifetime patterns of changes, particularly of adrenal androgens, suggest that such systems should exist. Normal androgenesis from the two axes and the mechanisms of androgen action are described, as an introduction to abnormal androgen action in women.