BACKGROUND: In patients with diabetes mellitus, chronic infections are frequent and severe, due to the impairment of their immune status. However, data on the prevalence of Helicobacter pylori (H. pylori) infection in diabetics are scanty and contradictory. The aim of our study was to assess the prevalence of H. pylori infection in diabetic patients and to evaluate the association between endoscopic features and H. pylori colonization of the gastric mucosa in diabetes mellitus. METHODS: A cross-sectional study of 172 dyspeptic patients (67 diabetics and 105 nondiabetic subjects) was designed. In all cases, an upper gastrointestinal endoscopy was performed, gastroduodenal lesions were noted, and the presence of gastritis and H. pylori was assessed by histopathological examination. Differences between diabetic patients and nondiabetic subjects were evaluated. RESULTS: The difference of H. pylori prevalence between diabetics (37.3%) and nondiabetics (35.2%) was not significant (P=0.78). Nor did the prevalence of gastritis and peptic ulcer differ significantly between the two groups (59.7% vs. 49.5%, P=0.19; and 32.8% vs. 40.9%, P=0.08, respectively). Studying only H. pylori-positive patients, we found no difference between diabetics and nondiabetics with regard to the prevalence of either gastritis (80% vs. 72.9%, P=0.71) or peptic ulcer (91.8% vs. 76%, P=0.09). CONCLUSIONS: Our data do not support an association between H. pylori infection and diabetes mellitus. This is confirmed by the lack of difference between diabetics and nondiabetics with regard to the prevalence of both H. pylori infection and H. pylori-related gastroduodenal disorders.