To investigate the relationship between lymphocytic gastritis and H. pylori infection, antral biopsy specimens from 162 patients with histological evidence of H. pylori infection, and from 177 subjects without colonization were retrospectively examined. Among patients with antral colonization, lymphocytic gastritis was identified in 8 cases (4.9%). Lymphocytic gastritis was not detected in specimens without H. pylori infection. Quantitation of the epithelial lymphocytic infiltration was carried out in all specimens and showed that cases with lymphocytic gastritis had a mean of 35.3 lymphocytes per 100 epithelial cells, compared with a mean of 2.6 and 2.4 respectively in chronic gastritis and normal mucosa. Among the 331 patients without lymphocytic gastritis, specimens colonized by H. pylori had a mean of epithelial lymphocyte counts significantly higher than those observed in both chronic gastritis and normal mucosa. These findings show a positive correlation between antral colonization by H. pylori and occurrence of lymphocytic gastritis, and suggest that the bacteria may have an important role in the induction of such particular form of antral inflammation.