A 24-yr-old female presented with a giant gastric ulcer and anemia. She suffered from a transient infantile malabsorption syndrome with eosinophilia. The diagnosis of eosinophilic gastroenteritis associated with the gastric ulcer was made by endoscopic biopsy. Ulcer healing was refractory to medical therapy and partial gastrectomy was performed. Histologic examination revealed transmural eosinophilic infiltrates with mast cell infiltrates in the gastric wall. This case illustrates (1) an extremely rare presentation of eosinophilic gastroenteritis--giant, refractory, gastric ulcer; (2) a potential pathogenic role for mast cells in this syndrome; and (3) the chronic and relapsing nature of the syndrome.