To determine the prevalence of lymphoid follicles in Helicobacter pylori(H. pylori) positive and negative gastritis and its relationship to age, biopsy site, gastritis activity, degree of gastritis, number of H. pylori and gastritis score in H. pylori associated gastritis, we examined the gastric tissue of patients with 121 nonulcer dyspepsia and 99 peptic ulcers. The gastritis score was obtained by adding together the figures for gastritis degree, gastritis activity and number of H. pylori. H. pylori was detected in 75.2% of nonulcer dyspepsia, 84.5% of gastric ulcers and 90.3% of duodenal ulcers. Lymphoid follicles were found in 63.3% of H. pylori associated gastritis and 4.7% of H. pylori negative gastritis, and there was a strong relationship between the prevalence of lymphoid follicles and H. pylori infection(P<0.01). Lymphoid follicles were found in 100% of H. pylori associated gastritis, showing severe chronic inflammatory cell infiltration, and strong relationship between the prevalene of lymphoid follicles and the degree of gastritis (P<0.01). There was no significant difference among lymphoid follicles, age, biopsy site, clinical diagnosis, gastritis activity and number of H. pylori. Lymphoid follicles were found in 58.3% of gastritis score 4, 67.6% of gastritis score 7 and 100% of gastritis score 9, and there was significant correlation between the prevalence of lymphoid follicles and a gastritis score(P<0.01, R=0.85). In summary, gastric lymphoid follicle is significantly associated with H. pylori infection and its presence in H. pylori associated gastritis is related to chronic inflammatory cell infiltration.