The frequency of occurrence of Helicobacter pylori type I strains in isolates from Austria and Portugal and different polymerase chain reaction-based approaches to detect the cag pathogenicity island were assessed. Of the 41 Austrian strains, eight of 14 (57.2%) isolated from patients with gastritis, 14 of 19 (73.7%) from patients with peptic ulcer and eight of eight (100%) from patients with gastric cancer were type I strains. Among the Portuguese strains, eight of 14 (57.2%) isolated from patients with gastritis, ten of 12 (83.3%) from patients with peptic ulcer and five of 13 (38.5%) from patients with gastric cancer were classified as type I. Thus, Helicobacter pylori type I strains occur frequently in both populations but show no significant correlation with peptic ulcer disease. The prevalence of the type Igenotype in Austrian cancer patients, however, was significantly higher (P=0.007). The cagE-specific polymerase chain reaction was found to be a reliable and efficient method for detection of the cag pathogenicity island.