Tympanosclerosis is the term used to describe a sclerotic or hyalin change of the mucous membrane of the middle ear and mastoid. Since Zöllner's report in 1956,1the lesion has been recognized more frequently by otologists.2-9With this increased awareness, however, it seems that some misunderstandings have developed as to the nature of the lesion and how it should be handled surgically. The opinion has been expressed by some5,7that the presence of tympanosclerosis is a contraindication of tympanoplastic surgery. We presented our thoughts on tympanosclerosis103 years ago and still hold to the opinions expressed. The purpose of this paper is threefold: to review the pathogenesis and pathology as we see it; to present the findings in a series of 75 cases, and to point out how the disease is handled surgically by members of the Otologic Medical Group. Pathogenesis and Pathology The tympanic cavity