Clinical study of 85 cases of major complications of chronic otitis media was done, experienced at the department of otolaryngology, Seoul National University Hospital between Jan., 1972 and Dec., 1978. Otogenic meningitis (22 cases), subperiosteal abscess (22 cases), facial palsy (21 cases), lateral sinus thrombophlebitis (7 cases), labyrinthitis (5 cases), epidural abscess (5 cases) and brain abscess (3 cases) were seen in order of frequency. Most common age group was between 10 and 29 years old group (59 cases). Major symptoms were ear discharge, hearing difficulty, headache, nausea and vomiting, vertigo, high fever and otalgia. On the X-ray findings of the temporal bone, sclerotic type was most common (65 cases) and bone destruction was seen in 30 cases. Tympanic membrane perforations were seen in all cases and important pathologic findings of the tympanum and the antrum were ossicle damage, cholesteatoma. Granulation with polyp and bone destruction. Operations were performed in 73 out of 85 cases. Radical mastoidectomy was performed in most cases (69 cases) and in 4 cases modified radical mastoidectomy was done. Unfortunately we could not approached operations in 12 cases because 9 were discharged for themselves due to poor economic condition and two patients were died before operation.