An outbreak of food-poisoning caused by a urea-hydrolyzing strain of Vibrio parahaemolytictis is presented. In the outbreak, urea-hydrolyzing V. parahaemolyticus was the only suspected etiological agent isolated from patients. In other respects, the strains conformed to the general characteristics of V. parahaemolyticus. The isolates were positive to the Kanagawa phenomenon and thermal direct hemolysin test. Urea-hydrolyzing strains of V, parahaemolyticus have rarely been reported and have not been described previously as a cause of food-poisoning in Japan. Eleven urea-hydrolyzing strains were found among the strains of V. parahaemolyticus isolated in our laboratory previously from various materials. Six of them were isolated from travellers to South-East Asia. A total of 16 strains of urea-hydrolyzing V.pamkaemolyticus was typed into 7 serovars (e. g. O4: K12, O6: K18, O1 : KUT. O3: K15 etc.).