Dysfunction of the auditory tube is an important factor in the development of middle ear diseases and is a common cause for failure in tympanoplasty. Therefore numerous technics and clinical procedures have been advised for assessing the function of the auditory tube. The aspiration-deflation method described by Flisberg (1963) is proved to be a more physiological test than others and has come into general use with the advent of the acoustic impedance bridge. Using the acoustic impedance bridge, we have studied auditory tube function of 147 patients (188 ears) who had perforated tympanic membrance due to chronic otitis media. The results were as follows : 1) Overall results of auditory tube function test revealed normal function in 36.2% mild dysfunction in 12.8%, poor function in 9.6%, and nonfunction in 41.5% by inflation method. By deflation method, normal function was noted in 23.4%, mild dysfunction in 6.4%, poor function in 11.7% and nonfunction in 58.5%. 2) In dry ear, normal function was noted in 53.1% by inflation, 33.3% by deflation method and in draining ear, normal function was noted in 18.5% by inflation, 13.0% by deflation which is showing good auditory tube function in dry ear. 3) In normal tympanic mucosa group, normal function was noted in 61.5% by inflation, 39.7% by deflation method and in abnormal tympanic mucosa group, normal function was noted in 13.1% by inflation and 7.1% by deflation method. 4) The percentage of normal function was a little bit higher in the low degree hearing loss group than in the high degree hearing loss group. 5) By Valsalva's maneuver, the overall positive rate was 57.4% and overall negative rate was 42.6%. Although the positive rate was higher (81.8%) as the function was good and the negative rate was higher (56.4%) as the function was bad, Valsalva's maneuver was not assessed as a good criteria for auditory tube function due to high false positive and false negative rate.