In order to investigate the characteristics of plain radiography of Ménière's disease, the degree of the pneumatization and the distance between the sigmoid plate and the bony wall of the vestibule in Schüller's view were examined in patients with unilateral and bilateral Ménière's disease, non-Ménière vertiginous disease and healthy subjects. There was no difference of the degree of pneumatization and the distance among the patients with Ménière's disease, the non-Ménière inner ear disease group and in healthy subjects. The distance of the unaffected ear was significantly shorter in patients showing a shorter distance of the affected ear. There was no relationship between the distance and age of onset of the disease, and duration of the disease. Therefore, it is concluded that the dysfunction of endolymphatic sac does not always reflect poor mastoid pneumatization and/or shorter distance in the plain radiography and that other etiological mechanisms such as autoimmune disease should be considered in some patients having evidence of endolymphatic hydrops.