V. fluvialis is a gram-negative, oxidase-producing, halophilic bacterium. It is normally found in coastal waters and seafoods. There have been a few reports on Vibrio fluvialis gastroenteritis in other countries, whereas there has been no previous report of V. fluvialis infections in Korea. Reports from other countries showed that V. fluvialis was isolated mostly from infants and children. We experienced a rare case of gastroenteritis due to V. fluvialis in a 55-year-old man with liver cirrhosis who ate an ark shell. He was admitted due to mild abdominal pain and severe watery diarrhea followed by rapidly progressive dehydration, electrolyte imbalance, and hepatorenal syndrome for a week. This patient was not improved by intensive care and antibiotic therapy.