Parietal cell antibodies were present in 12% of 272 Peruvians presenting for endoscopy. Gender, age, socioeconomic status, ethnic background (Peruvian versus Japanese), and altitude at which the patient lived were not associated with the presence of parietal cell antibodies. No significant relationship could be shown between the presence of parietal cell antibodies and either Helicobacter pylori infection or gastric lesions, including chronic atrophic gastritis. Loss of proper gastric glands was significantly more common in patients who had H. pylori infection than in those in whom no H. pylori was found on biopsy (78 of 114 (85%) versus 14 of 36 (39%); p = 0.002). Our data suggest that, although parietal cell antibodies are present in third-world populations, they are unrelated to H. pylori infection and that pathologic changes associated with this infection are not mediated by the action of parietal cell antibodies on the cells of the stomach.