A 15-year-old girl with primary amenorrhea, hirsutism, and enlargement of the clitoris was found to have an increased titer of the urinary neutral 17-ketosteroids which failed to decrease after the administration of dexamethasone and an adrenal tumor was demonstrable on venography. Analysis of the adrenal venous effluent revealed gradients on the side of the tumor for testosterone, androstenedione, estradiol, and dehydroepiandrosterone sulfate. Following removal of the tumor, the hirsutism improved markedly, the menses returned, and sexual maturation progressed.