Non-ulcer dyspepsia is a common disorder in clinical practice. The pathogenesis and predisposing factors that lead to the development of Helicobacter pylori infection are still unclear. The aim of the present study was to evaluate the prevalence of H. pylori infection in non-ulcer dyspepsia patients with delayed gastric emptying and those with normal gastric emptying, and to determine if delayed gastric emptying predisposes to H. pylori infection. A total of 70 patients (29 males, 41 females) aged 18-59 years (mean +/- S.D. 40.5 +/- 11.2 years) took part in the study. A solid-phase scintigraphic gastric emptying study and 14C urea breath test were performed on each patient. There was no statistically significant difference in age between those patients with and without delayed gastric emptying (40.8 +/- 11.9 vs 40.4 +/- 10.5 years), or between those with and without H. pylori infection (40.5 +/- 12.6 vs 40.5 +/- 9.8 years). Of the 70 patients, 45 (64.3%) had delayed gastric emptying and 25 (35.7%) had normal gastric emptying. The overall incidence of H. pylori infection was 58.6%. The incidence of H. pylori infection among patients with delayed gastric emptying was 60% (27/45 patients) and among patients with normal gastric emptying 56% (14/25) patients). The incidence of H. pylori infection in the two groups was not significantly different. The incidence of H. pylori infection in the non-ulcer dyspepsia patients in this study was similar to that of age-matched asymptomatic volunteers in Taiwan. In conclusion, based on the results of this study, delayed gastric emptying does not lead to a predisposition to H. pylori infection in non-ulcer dyspepsia patients.