A case of thyroiditis due to Brucella Melitensis is reported. Brucellosis anticipated by about two months the onset of the characteristic symptoms of acute thyroiditis. Cultures of specimens obtained by fine needle aspiration biopsy and microbiological investigations allowed isolation and identification of the germ. This observation allowed the recognition that thyroid gland might harbored secondary localization of a prolonged brucellosis. A microbiological study (the protocol of which is proposed) of specimen obtained by fine needle aspiration biopsy should be performed in the presence of symptoms and signs of an inflammatory process associated to an acute swelling of the thyroid gland.