This report was presented on the clinical and histopathological findings of the interesting two cases of tympanosclerosis experienced recently. The two cases were 22 and 26 year-old females who had chief complaints of progressive hearing loss after chronic mucoid otorrhea since her childhood. In case 1, the incus including the body and long process was almost completely surrounded by gray-whitish firm masses extending to the upper portion of the tympanum and oval window. After removing the masses including the incus and head of the malleus, tympanoplasty type III was performed. In case 2, handle of the malleus and long process of the incus were partially surrounded by chalky-white sclerotic mass. After removing the mass, tympanoplasty type II was done. Histopathological findings showed hyaline degeneration of the mucous membrane of middle ear, some containing the calcification on the deeper stroma.