The purposes of this study were to evaluate the effect of inflating the Eustachian tube in patients with tinnitus, and to identify diseases in which tubal inflation is indicated. Fifty-four ears of as many patients complaining of tinnitus were examined by pure tone audiometry and decreases in pitch and loudness associated with tinnitus were also evaluated by tinnitus audiometry (Danac-100, DanaJapan). Tinnitus was associated with sensorineural hearing loss (SNHL) in 44 ears and not associated in the remaining 10. The subjects were classified further into two groups: the higher tone group showed a pitch range with tinnitus of 1000 Hz or higher, and the lower tone group showed a pitch range of less than 1000 Hz. In the higher tone tinnitus group with SNLH, the tubal inflation was effective in 3 of 31 ears (10%), and in the lower tone group, 10 of 13 ears (77%). On the other hand, in the tinnitus group with no hearing loss, the method relieved tinnitus in 6 of 10 ears (60%). In the higher tone tinnitus group with no hearing loss, the tubal inflation was effective in 3 of 6 ears (50%), and in the lower tone group, 3 of 4 ears (75%). In this study, however, no ears were permanently relieved of tinnitus with tubal inflation. In the higher tone group, the duration of the reduced tinnitus was less than 10 minutes. In 69% of the lower tone group, the reduction was from 20 minutes to 2 hours. The effect did not continue for more than 2 hours at the longest. In conclusion, Eustachian tubal inflation is indicated in diseases with tinnitus as follows: 1. Lower tone tinnitus with SNHL, particularly in Meniere's disease and acute onset low-tone type SNHL, may be temporarily relieved with tubal inflation. 2. Tinnitus in an ear without SNHL that may gain transitory relief from ringing with the tubal inflation.