Collagenous gastritis is a rare entity, characterized by the deposition of a subepithelial collagenous band with an inflammatory infiltrate in the mucosa. We report the first Tunisian case revealed by severe anemia. Lesions were limited to the stomach and remained unchanged on 3 series biopsies during a 24 month follow up despite treatment with corticosteroids. The cause of the disease remains unknown; our findings suggest that lesions of collagenous gastritis may result from a local immune process.