The audiometry was performed on 1525 of primary school pupils (3rd to 6th year) and 1548 of junior high school students (1st to 3rd year), numbering a total of 3073. The audiogram was examined on those who had hard of hearing probably caused by adenoids. Also, adenoidectomy was performed on them and the change in audition had been observed afterwards for some time. The results were as follows:
1. The proportion of not-having normal auditory threshold in all the examined was 17.8% as average (19.41% in primary school and 16.86% in junior high school).
2. The proportion of not-having subjective symptoms of hearing impairment in them (1) was 65.99% as average (73.0% in primary school and 56.57% in junior high school).
3. Adenoids were definitely observed in 64.86% of primary school pupils and 54.18 % of high school students in the cases of hearing impairment and high percentage 59.96% was ob- served among all cases.
4. The scholastic estimation of them, including adenoids cases, was mostly- the low, accor- ding to 3 grades (upper, middle and low) classification. And this tendency was more remarkable in primary school than in junior high school.
5. Air conduction hearing test of adenoids cases showed mostly A and B type, according to the Kawata's classification, followed by D, C, E, W, and dip type. The impairment of only the high frequencies area was particularly noticeable, compared with the cases in which only the low frequencies showed the hearing losses.
6. Bone conduction hearing test showed normal audition in most cases and showed slight loss at 800 cps and 250 cps.
7. Earplug bone conduction test (Onchi's) was negative in most cases.
8. In two cases out of 18 which had been given balance test (Fowler phenomenon), positive recruitment of loudness was observed.
9. Air conduction-audiogram after the performance of adenoidectomy showed the recovery in 89.34% a week later, 93.44% in two weeks, 88.8% in three weeks and 97.1% a month later as average of all cases.
10. Valuable meaning could not be recognized in the relationship between hearing acuity and the size of adenoids tissue acquired by opeation.

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