The hypopituitarism and the diabetes insipidus are often idiopathic. A retrospective study of 6 cases of diabetes insipidus and 8 cases of partial or total idiopathic antehypophyseal insufficiency has shown the value of MRI to demonstrate anomalies of the infundibulum or hypothalamic-hypophysis "stages". MRI allows to bring together some cases of idiopathic hypopituitarism in a new entity which is the hypopituitarism due to a newborn section of the infundibulum.