A case of late hydrocephalus due to gliosis of the cerebral aqueduct, complicated with cerebrospinal fluid rhinorrhea, is reported. The fistula was formed by a large communication between the very dilated 3rd ventricle and the sphenoidal sinus, in consequence to a erosin of the sellar floor. The patient was operated on and the fistula satisfactority blocked; previously was made a ventriculo-peritoneal shunt to avoid the recurrence of the ventricular hypertension.