Sliding hiatal hernia is a common endoscopic finding with a prevalence that increases with the age of patients. Although nearly all patients with GERD have HH, only a minority of patients with hernia reports reflux symptoms. Our hypothesis is that H. pylori infection may be responsible for the high number of asymptomatic hernias. After exclusion of patients with peptic ulcer, 507 patients with an endoscopic diagnosis of hernia were considered. Patients were divided into three groups: A, < or = 45 years, 141 patients; B, 46-60 years, 144 patients; and C, > or = 61 years, 222 patients. Presence of reflux symptoms (questionnaire) and esophagitis, H. pylori status, and gastric histology were recorded. The prevalence of hernia in the total series was 11% in group A, 23% in B, and 38% in C. Aging was associated with a significant increase in H. pylori prevalence and corpus gastritis scores, and a parallel decrease of GERD symptom prevalence, which was 66.6% in group A, 52.1% in B, and 46.8% in C (P < 0.01). Taking the three groups together, prevalence of H. pylori infection was higher in patients without GERD than with GERD (66.4 vs 57.3%, P < 0.05), and higher in patients with nonerosive GERD than erosive GERD (62.8 vs 48.6%, P = 0.02); corpus gastritis scores were significantly higher in patients without GERD than those with GERD and in those with nonerosive than erosive GERD. In conclusion, H. pylori infection protects against development of GERD in subjects with hiatus hernia. This effect is significantly more evident in the elderly where, in spite of the high prevalence of hernia, only a small number of individuals develop GERD. The development of a corpus-predominant gastritis is probably responsible for this effect.