OBJECTIVE: Several studies have demonstrated that chronic exposure to gluten may damage the structure and function of the gastric mucosa in gluten-sensitive patients. However, until now, these abnormalities have been incompletely studied. Our purpose in the present study was to characterize, in a prospective controlled study, the endoscopic and histological appearance of the gastric mucosa in a large cohort of patients with celiac disease with and without Helicobacter pylori (H. pylori) infection. METHODS: We evaluated biopsy specimens taken from the gastric body and antrum of 218 individuals who underwent upper endoscopy for small bowel biopsy. One hundred-four patients had celiac disease (80 of them at the time of diagnosis-untreated). In 114 subjects celiac disease was excluded. RESULTS: Endoscopic findings did not show a difference between the groups. The prevalence of cases with normal gastric mucosa, chronic superficial gastritis, and atrophic gastritis was similar in patients and controls. Similarly, presence of metaplasia, inflammatory activity, and lymphoid follicles and aggregates did not show differences between the groups. Histological or serological evidence of H. pylori infection was detected in 86% of patients (82% of untreated celiacs and 95% of those on those taking treatment). The infection was highly prevalent in patients (89%) and controls (97%) diagnosed with chronic gastritis. Untreated patients had a significant greater IEL count in the antrum and corpus than controls (p < 0.0001 and p < 0.001, respectively). A global analysis of the data on intraepithelial lymphocyte (IEL) counts in the different populations suggest that the inflammatory state may represent the cumulative effect of H. pylori infection and gluten sensitivity. Only three patients had IEL infiltration compatible with diagnosis of lymphocytic gastritis (count >25%) and three other patients had borderline counts. CONCLUSIONS: According to our results, celiac disease patients presented a similar prevalence of gastric mucosal abnormalities compared with the control population. Evidence of H. pylori infection was very high compared with the prevalence in the general Argentine population. As a particular observation in our celiac population, the disease was rarely associated with lymphocytic gastritis. We suggest that the chronic inflammatory state evidenced by a gastric mucosal lymphocyte infiltration may be secondary to the combination of H. pylori infection and chronic gluten ingestion in gluten-sensitive subjects.