Clinical etiologic evaluation of otitis media with effusion(OME) during past 5 years were observed. Age, sex and laterality, pure tone audiogram(PAT), types of tympanogram, recurrence rate were also reviewed. The number of ears for clinical observation was 800 ears(492 patients) consisting of 535 ears(301 patients) in children and 265 ears(191 patients) in adults. The results were as follows : 1) The clinical etiology of OME. a) In the all age group, the incidence was Rhinosinusitis(43.7%), adenoid vegetation(AV), (26.6%), URI(21.5%) in the order. b) In the adult group, Rhinosinusitis(46.4%), URI(36.7%), Nasopharyngeal Ca(6.1%) in the order. c) In the adolescent group, Rhinosinusitis(72.0%), URI(19.3%) in the order. d) In the children group, Rhinosinusitis(40.1%), AV(38.2%), URI(16.6%) in the order. 2) The age distribution was most common in the age from 2 to 6 years(28%), and 7 to 12 years(24.4%). 3) Bilateral effusion was 234 case(77.7%) in the age below 19 years and unilateral effusion was 117 case(61.3%) in the adults.