V. parahaemolyticus or V. alginolyticus infections are usually associated with consumption of raw or undercooked shellfish, contaminated food, and exposure of wounds to warm seawater. V. parahaemolyticus causes gastroenteritis (the most common syndrome), wound infections, and septicemia. V. alginolyticus occasionally causes extraintestinal infections in humans. So far, the authors have not found the report of V. parahaemolyticus and V. alginolyticus isolation from a patient. So, we report a case of concurrent isolation of V. parahaemolyticus and V. alginolyticus from a patient who had a history of intestinal diarrhea and vomiting. (Korean J Clin Microbiol 2000;3:147-150)