A Clinical study was performed in 116 cases of chronic otitis media with cholesteatoma, who had taken the middle ear surgery at dept. of Otolaryngology, Choongnam National University Hospital during these two years. The results were as follows : 1) Age distribution showed predilection for 2nd and 3rd decades with 45.7% and 29.3% but there was no significant difference between both sexes. And most of them had long term history of otorrhea. 2) On the findings of ear drum perforation, there was total defect of drum in 49.1%, attic perforation in 39.6%, perforation on posterosuperior portion in 9.5% and central perforation in 1.8%. 3) Preoperative pure tone audiometric findings showed mixed hearing loss in 47.8%, conductive hearing loss in 46.0%, total loss in 4.4% and normal in 1.8%. 4) On operative findings, 48.3% of them had slight edematous or nearly normal tympanic mucosa, 37.0% granulation and 12.1% polyp. 5) Destruction of ossicles was noted in 92.3% of cases ; total loss in 56.9%, destruction of malleus and incus in 28.4%. 6) Cholesteatoma extended to the epitympanum, antrum and mastoid in 24.1% of cases, epitympanum, tympanum, antrum, and mastoid in 22.4%, epitympanum and antrum in 20.6%, epitympanum in 19.0%, epitympanum, tympanum and antrum in 10.4% and epitympanum and tympanum in 3.5%. 7) Bacteriological study from cholesteatoma showed single infection in 91.0% of cases and 73.2% of cases were Gram negative orgnisms. The most common infected organism was Proteus species(45.3%) and Staphylococcus(18.8%). 8) Complications of cholesteatoma were observed in 43.1% of cases : Subperiosteal abscess in 13.8%, facial palsy in 6.1%, lateral semicircular canal fistula in 12.9%, including 5 cases with dead labyrinth, and pathologic exposure of dura in 14.6%, including 13 cases with intracranial complications. 9) The mastoidectomy with tympanoplasty was done in 56.0% of cases, with or without tympanization in 42.2% and tympanoplasty in 1.8%. And all of mastoidectomy were performed with open cavity technique. 10) Postoperative complications were postoperative infection in 3.5% at 12th month, dry perforation in 7.7%, recurrent cholesteatoma in 1.8% and dead labyrinth in 0.9% of cases. 11) Postoperative hearing at 12th month was improved but it had unsatisfactory results.