Background & Objectives: Hearing is perhaps the most important sense in human beings without which communication with the environment would greatly diminish. Chronic perforation of tympanic membrane, ossicular erosion and tympanosclerosis are major causes of hearing diorders. Nevertheless, a conducting hearing loss is the commonest complication of chronic otitis media. Cholesteatoma which is the most dangerous complication of chronic otitis media is treated by surgery. Tympanosclerosis is also one of the most important complications of chronic otitis media, which leads to conductive hearing loss through ossicular fixation. This study is an attempt to determine the effect of different kinds of chronic otitis media on the hearing of the patients.

  Methods: In this survey, 440 patients with chronic otitis media, who were surgically treated in the department of otolaryngology between 1998-1999, were studied in terms of various pathology of middle ear and the resultant level of hearing impairment.

  Results: 37 patients (8.4%) were involved bilaterally with otitis media. The number of operations on the left ear was 10% more than those on the right. The most common pathology recognized in examination was nonprulant perforation of tympanic membrane in 179 cases (40.7%) and the most common pathology recognized in surgery was cholesteatoma in 140 cases (30.2%). From 440 patients, 430 cases had conductive hearing loss and 92 cases (20.9%) had sensorineural hearing loss. Cholesteatoma of middle ear caused the highest proportion of conductive hearing loss and majority of the cases with sensorineural hearing loss (about 30%) whereas tympanosclerosis caused the most severe sensorineural hearing losses.

  Conclusion: The findings indicated that cholesteatoma and tympanosclerosis were the most common causes of both conductive and sensorineural hearing loss with tympanosclerosis as the cause of the most severe sensorineural hearing loss. However granulation tissue is the most common histopathology in patients with chronic otitis media at references and papers.