An empty sella was demonstrated on air study in five patients with the benign intracranial hypertension (BIH) syndrome. All patients had a protracted course and very high cerebrospinal fluid pressure; two required a shunt procedure. No patient had any endocrine symptoms or visual field defects but an air study was done to exclude a mass lesion in the sella region. Among the last 50 patients seen with the BIH syndrome, there were five cases of an associated empty sella (10%). In these cases, the empty sella is a probable consequence of the long-standing intracranial hypertension associated with a congenital deficiency of the diaphragma sellae.