Acute otitis media caused by vibrio alginolyticus is a rare disease and reported 18 cases in the foreign-literature, but not reported in Korea. Authors recently experienced a case of acute otitis media caused by vibrio alginolyticus confirmed by bacteriologic study. The patient was 32 years old female who has been suffered from ear fulling sensation, autophonia, mucopurulant otorrhea and mild hearing disturbance in association with U.R.I. after swimming in the sea water this summer. Conservative theraphy including antibiotics(chloramphenicol) cured the otitis media.