Eosinophilic gastroenteritis is a rare condition of unknown cause characterized by pheripheral eosinophilia and eosinophilic infiltration of the gastrointestinal tract. Eosonophilic gastroenteritis is generally classified according to the layer of the gastrointestinal tract that is involved. Serosal eosinophilic infiltration is the rarest form of presentation and can result in the development of eosinophilic ascites. We experienced a case of eosinophlilic gastroenteritis involving the entire gastrointestinal tract in a 34-year-old female patient with abdominal pain that was confirmed by multiple biopsies of the gastrointestinal tract with eosinophilic ascites. The patient was successfully treated with corticosteroids. We report this case with a brief review of the literature. (Korean J Gastrointest Endosc 2008;36:282- 287)