This case report describes a virilizing adrenoc01tical carcinoma in an 11-year-old male castrated domestic sho1thair. While adrenal tumors are rep01ted in cats, they are not as common as in canines and previous reports of virilization, or development of male secondary sexual characteristics, as a result of abnormal hormone production from the adrenal glands are rare. Adrenal virilism may be due either to congenital adrenal hyperplasia as a result of a deficiency of an enzyme critical to cortisol or aldosterone synthesis, or due to a secretory adrenal tumor. In this patient, removal of the left adrenal gland via ventral midline resulted in a complete resolution of clinical signs, leading to a presumptive diagnosis ofvirilizing adrenocortical carcinoma. Secretory adrenal masses should be considered as a differential in older castrated patients displaying physical characteristics and behaviors consistent with intact animals.