A patient had bilateral testicular tumors complicating the adrenogenital syndrome. This is the first such instance of the complication fully documented to have occurred with the simple virilizing type of congenital virilizing adrenal hyperplasia (CAH) and the first demonstration of cortisol synthesis by the testicular tumors associated with this disorder. A review of the literature concerned with the origin of these testicular tumors suggests that they arise primarily from testicular interstitial cells under the stimulus of increased plasma adrenocorticotropic hormone (ACTH).