Over a six-year period we detected 30 clinical infections caused by halophilic vibrios in a restricted geographical area. Vibrio parahaemolyticus infections were found in 13 patients (three with wound infections, ten with ear infections), and Vibrio alginolyticus infections in 17 patients, all of whom had ear infections. From 1987 to 1990, infections caused by marine vibrios were found in at most four cases annually, in 1992 in six instances, whereas over a five-month period in 1991 we experienced 15 cases of extraintestinal infections. Fifteen of the infections found in 1991 and 1992 were ear infections, ten of which occurred shortly after exposure to Danish coastal seawater. The disease was mild in most of the patients and all recovered. Most of the patients showed predisposing conditions such as chronic otitis media, perforation of the tympanic membrane or ulcus cruris. The organisms were isolated in minor numbers from coastal water samples from five of 12 bathing areas around Funen at the end of July, but not at the end of November. This study indicates that halophilic marine vibrios may be pathogenic in Denmark in persons exposed to seawater.