Congenital adrenal hyperplasia due to 17 alpha-hydroxylase deficiency in genotypic females is characterized by primary amenorrhea and the absence of sexual maturation due to inadequate biosynthesis of ovarian androgens and estrogens. We induced ovarian follicular development in a woman with this syndrome. Ovum pick-up, in vitro fertilization, and primary embryonic development were achieved despite undetectable plasma estradiol and extremely low ovarian androgen concentrations and minute concentrations of these hormones in the ovarian follicular fluid.