SOME FACTS speak in favor of the assumption that in present-day otology chronic adhesive otitis, instead of manifest suppurative chronic otitis, will become the commonest inflammatory disease of the middle ear leading to serious deterioration of hearing. Thanks to modern antibacterial agents, it seems possible that development of manifest suppurative chronic otitis can in most cases be prevented by proper therapy. In spite of the new drugs, prevention of chronic adhesive otitis can hardly be equally successful, owing to the somewhat obscure origin and insidious development of this disease. On the contrary, there is reason to believe that some conditions which previously would have resulted in manifest suppurative chronic otitis may now develop into chronic adhesive otitis. It thus seems that a reconsideration of chronic adhesive otitis is appropriate. As regards clinical characteristics, there is a close resemblance between chronic adhesive otitis and otosclerosis. Probably some of the lesions diagnosed