Empty sella syndrome is an anatomical entity in which the pituitary fossa is enlarged and partially filled with cerebrospinal fluid owing to the arachnoid herniation, while the pituitary gland is compressed against the posterior rim of the fossa. This condition can be due to an inherent weakness of the diaphragm sella and/or to an increase in intracranial pressure which promote the herniation of the arachnoid membrane into the pituitary fossa (primary empty sella) or it can results following surgery, radiation or vascular and tumorous pituitary diseases (secondary empty sella). Empty sella can be associated with neuroradiological and endocrine symptoms. This study reports the clinical, endocrine, and roentgenographic features in 20 patients with primary empty sella syndrome. Disturbances of hypothalamic-pituitary function were detected in 6 patients (hyperprolactinemia, hypopituitarism, central diabetes insipidus, hypothalamic hypothyroidism). Three patients exhibited hypergonadotropic hypogonadism. This report supports the following conclusions: a) there is no correlation between size of pituitary fossa, type an extension of arachnoid herniation and the degree of hypothalamic-pituitary dysfunction; b) endocrine alterations are frequent in the empty sella syndrome; c) the association of empty sella and primary diabetes insipidus is not a very rare event.