The great variability in gastric cancer rates across Asia, with very high incidences in Japan and Korea, andexceedingly low incidences in ethnic Malays, whether in Malaysia or Indonesia, appears largely due to variationin Helicobacter pylori infection rates. While between 2% and 10.6% of gastric cancers in a recent Japanesesurvey were considered to be negative for bacterial infection on the basis of seropositivity and H. pylori-dependentmucosal atrophy, it is notoriously difficult to preclude past infection. The situation is greatly complicated byreported differences in the etiology of gastric cardia and non-cardia cancers. In the Western world there doappear to be tumours arising close to the esophageal-gastric junction which are not related to H. pylori andassociated inflammation, but in most Asian populations these appear to be very rare. Therefore preventiveefforts, and particularly screening, should be focused on markers of bacterial infection, with avoidance ofunnecessary exposure to X-ray radiation.