Diabetic patients often suffer from symptoms arising from the gastrointestinal tract. Several factors are considered responsible for these alterations, including abnormalities of gastric motility. Recently Helicobacter pylori (HP) has been identified in a relevant aliquot of subjects with or without gastrointestinal abnormalities, but only scarce and controversial data are available on the prevalence of HP and the association between HP and chronic gastritis or peptic ulcer in diabetic patients. In addition, the possible association between alterations of gastric motility induced by autonomic neuropathy (AN) and the presence of HP has never been evaluated in diabetic subjects. In this study we document the presence of HP in the gastric biopsies of 73% out of a series of 29 patients affected by type 2 diabetes and non-ulcer dyspepsia (3 with oesophagitis, 10 with gastritis, 7 with bulbar duodenitis, and 9 with a normal endoscopy), with a significantly higher prevalence (P < 0.01) in subjects with AN (74%) than in subjects without AN (26%). Two other tests have been compared with the histological evidence of HP (used as golden standard), i.e. the urease test (CP-test) and the assay of anti-HP G-immunoglobulins, both of which were positive in a significantly (P < 0.01) higher percentage of neuropathic patients in comparison with non-neuropathic patients. The sensitivity and the specificity of the CP-test were 96% and 100%, respectively. Similarly, both the sensitivity and the specificity of the assay of IgG HP-Ab were 100%. Since patients affected by non-ulcer dyspepsia and NIDDM complicated by autonomic neuropathy are under a higher risk to be carriers of HP than non-neuropathic or non-diabetic patients. The assay of serum IgG HP-Ab could be used as a screening method, thus avoiding the more expensive and time-consuming endoscopy.