One of the gastric biopsy specimens taken from a 53-year-old male showed localized accumulation of plasma cells containing Russell bodies, in association with infection of Helicobacter pylori (H. pylori). An endoscopic study demonstrated multiple ulcer scars in the antrum. Immunohistochemically, H. pylori infection was identified both on the surface of the foveolar epithelial cells and in the cytoplasm of macrophages in the lamina propria mucosae. Plasma cells filled with 'Russell bodies', so-called 'Motts cells', were immunoreactive for CD45, CD79a and IgG. This seems to be a previously unrecognized tissue reaction in gastric mucosa associated with H. pylori infection, which we have called 'Russell body gastritis'.