The handicap of hearing loss is in direct proportion to the effect that the loss has on the patient's communication. An estimate of the effect of the hearing loss on speech can be made from the pure tone audiogram. In 1959 a new method for computing percentage hearing impairment was published under the sponsership of the American Academy of Ophthalmology and Otolaryngology, and hence it is referred as the A.A.O.O. method. In the A.A.O.O. method, only the speech frequencies are assigned any percentage value. Hearing loss and percentage hearing loss were evaluated in 145 cases of chronic otitis media. The results were as followings ; 1) Hearing loss in 51 unilateral cases was from 43.4 dB to 51.2 dB in each age group without significance of age. 2) Hearing loss of healthy ear in 51 unilateral cases was from 7.8 dB to 17.5 dB in each age group with slight loss at high frequencies in older age group. 3) Hearing loss of right ear in 94 bilateral cases was from 38.4 dB to 55.8 dB and hearing loss of left ear was from 35.8 dB to 48.3 dB in each age group without significance of age. Consequently no significant difference of hearing loss between right and left ear was noted. 4) Percentage hearing loss was from 2.3% to 11.4% in unilateral cases and from 17.9% to 37.3% in bilateral cases, without significance of age. Consequently, percentage hearing loss was more severe in bilateral cases than in unilateral cases.