While reviewing gastric specimens from 215 baboons, we found diffuse giant mucosal folds in 2 specimens and multiple giant mucosal nodules in another 3. The increased mucosal thickness in those areas was due to giant hyperplasia of the foveolar epithelium. The former 2 specimens were classified as Menetrier's disease (MD) and the latter 3 as Varioliform Lymphocytic Gastritis (VLG), since they were histologically identical to those gastropathies in humans. Whereas MD had diffuse giant hyperplastic foveoli (without lymphocytic infiltration) and prominent glandular cysts, VLG had nodules due to giant hyperplastic foveoli with intraepithelial lymphocytosis. Since the causes leading to gastric MD and VLG in humans remain unknown, the spontaneous occurrence of these two conditions in the baboon may open new avenues for the investigation of possible etiologic factors in the laboratory.