Lymphocytic gastritis (LG) is an uncommon chronic gastritis characterized by lymphocytosis of foveolar and surface epithelium. Lymphocytic gastritis is associated with celiac disease, Helicobacter pylori (HP) gastritis, and varioliform gastritis, but its topology and severity with respect to the associated entities have not been studied in detail. Therefore, we studied 103 patients with LG classified according to the associated entities, including the distribution and severity of LG in the 70 patients from whom biopsy specimens of both antrum and body were available. In 84 patients (82%), a distinct associated entity was identified, including 39 with celiac disease, 30 with HP infection, 4 with varioliform gastritis, 2 each with inflammatory polyp, Crohn's disease, human immunodeficiency virus infection, lymphoma, and esophageal carcinoma, and 1 with lymphocytic gastroenterocolitis. Lymphocytic gastritis was found in 33% of patients with celiac disease and 4.1% of histopathologically defined HP gastritis. The severity of intraepithelial lymphocytosis was greater in antrum than in body in 83% (20 of 24) of LG associated with celiac disease, but in only 19% (4 of 21) of LG associated with HP infection (p < 0.00002). All four patients with varioliform gastritis had more severe involvement of body. Lymphocytic colitis was common (38%, 5 of 13) in celiac disease with LG. Our results indicate that lymphocytic gastritis most commonly occurs in celiac disease and HP infection, but rarely with other entities. The topology of LG can direct the clinical evaluation for associated disease.