Gardner's syndrome (GS) is a dysplasia characterized by neoformations of the intestine, soft tissue, and osseous tissue. Endocrine neoplasms have occasionally been reported in association with GS. Adrenal masses in GS are rare, and few have displayed clinical manifestations. In the current paper, The authors report a 37-year-old male patient with GS including familial adenomatous polyposis (FAP) and mandible osteoma who presented with an incidental adrenal mass. Computerized tomography adrenal scan identified bilateral masses. Functional analyses showed a hormonal secretion pattern consistent with pre-Cushing's syndrome. Other extraintestinal manifestations were hypertrophy of the pigmented layer of the retina and histiocytofibroma in the right leg. This paper describes a rare association of adrenocortical secreting mass in an old male patient with Gardner syndrome.