In 71 patients with adhesive processes the development and rate of recidives after tymplasty is studied by clinical and tympanometric observation. The typical tympanogram in adhesive processes is flattened with a peak in the negative pressure area. Initially after tympanoplasty permanent aeration was secured by grommets. When these came out and the tympanic membrane was closed, most of the cases showed almost normal tympanograms. Within 3 months in most cases the preoperative tympanogram re-developed, regardless what the tube function was like. The typical peak in the negative area must not necessarily be caused by negative pressure in the middle ear - as we could demonstrate in model studies. These results correspond closely to the clinical findings. The enlargement of the middle ear cavity by tympanoplastics can only be obtained by permanent aeration. When the tympanic membrane is closed - regardless of the tube function - often new retractions occur, which can easily lead to recidives of the adhesive process. Hearing tests showed close correlations to the tympanometric findings. Hearing is improved as long as the grommet secure permenent aeration; when the tympanic membrane is closed, it may become worse during a very short period. Correlations between hearing and the mobility of the tympanic membrane and ossicles in adhesive processes could be shown in the tympanoaudiogram.