Adrenogenital Syndrome, more properly defined as Congenital Adrenal Hyperplasia (CAH), is related to the enzyme 21beta-hydroxylase deficiency, with impaired glucocorticoids and aldosterone syntheses and increased ACTH synthesis. This report describes a case of a monorchid patient suffering from Adrenogenital Syndrome and Leydig cell tumor of his testis. A right orchidectomy with implantation of testis prosthesis was performed, after informing the patient on the consequences of his castration and obtaining his consent. Histology showed a testis measuring 4x3x2.5 cm with a 6 cm long spermatic cord; there was a yellowish, well-defined nodule measuring 3.5x1.5 cm, surrounded by normal parenchyma. This nodule had morphologic and immunohistochemical characteristics of a Leydig cell tumor, even found in the spermatic cord; those cells showed positivity to inibine, MART-1 and vimentine.