We report a case of Ménétrier's disease associated with hypoproteinemia who was successfully treated by eradication of Helicobacter pylori infection. A 26-year-old woman had diffuse giant gastric folds with proven protein leakage from the stomach. She received cimetidine, famotidine, and omeprazole for more than 3 months with little benefit. H. pylori infection was detected, and she was treated with clarithromycin (200 mg three times a day), lansoprazole (30 mg/day), and ecabet sodium (1.5 g twice a day) for 2 weeks. After starting the treatment, rapid increase of serum albumin and IgG levels were observed. The treatment resulted in eradication of H. pylori infection, and serum albumin and IgG levels returned to normal. Histologic specimens also showed the improvement of the irregularly elongated gastric pits with inflammatory infiltrates after the treatment. This case report suggests that eradication of H. pylori is recommended therapy for the immediate improvement of Ménétrier's disease associated with hypoproteinemia.