A new theory is put forward to the effect that chronic middle-ear disease results directly from secretory otitis in childhood. The theory is based on an analysis of different materials, including healthy children in various age groups who were followed with tympanometry over a long period of time; children with secretory otitis who were re-evaluated 3-8 years after treatment, with special reference to changes in the tympanic membrane; and an otosurgical group comprising 1,100 ears, which were re-evaluated 3-14 years after operation. Chronic secretory otitis and chronic tubal dysfunction, which are particularly frequent in childhood, may cause such changes in the tympanic membrane and/or middle ear, that conditions are created which later on, maybe years after remission of secretory otitis, may favour the development of cholesteatoma, non-cholesteatomatous chronic otitis and perforation of the tympanic membrane.