In this case-report we describe two patients with hypothyroidism and increased carcinoembryonic antigen (CEA) serum concentration. The former patient was a woman affected by primary autoimmune hypothyroidism, the latter by secondary hypothyroidism in empty sella syndrome. In both of the patients we found no evidence of neoplastic disease and CEA serum concentrations reverted almost completely to the normal range values after the patients were given the hormonal replacement therapy with L-thyroxine. Although the association of hypothyroidism with elevated CEA serum concentrations has been already reported in the literature, hypothyroidism is usually disregarded when a physician is facing with a patient with increased CEA levels. On the contrary, our data suggest that hypothyroidism should be taken into account in the diagnostic work-up of these patients, such as smoking, cholestasis, impaired liver function, chronic inflammatory bronchial and bowel disease.