In 224 numbered tonsillectomized and adenotonsillectomized children under 15 year's age, we had studied in clinical view points of out and admitted patients who passed over one year's period after operation during 3 year's from 1976 to 1979. Following results were obtained. 1) The most common cause of operation was Frequent URI and Sore Throat with 62.1% ratio. 2) Local and accompanied symptoms were moderately improved with 76.8%. (1) Frequent URI with Sore Throat was improved in 82.9%, (2) Frequent Sore Throat was in 78.6%, (3) Nasal Symptoms was in 59.3%, (4) Mouth Breathing was in 73.5%, (5) Hearing Impairment was in 72%, (6) Cervical Lymphadenitis was in 90%. 3) Systemic diseases such as bronchopneumonia, rheumatic fever, glomerulonephritis were improved and their secondary attack ratio was much decreased than preoperative states.