We previously noted an extraordinarily high number of cases of primary gastric lymphoma (PGL) in northeastern Italy. We have now formally compared the incidence in Feltre, Italy, with that in three similar communities in the UK. Each community has a stable population served by a single endoscopy unit and histopathology laboratory. There were 13 times more cases of PGL in Feltre in 1986-91 than in the UK communities (66 vs 5 per 100,000 per 5 years). The incidence of gastric adenocarcinoma was also substantially higher in Feltre than in the UK (270 vs an average of 82 per 100,000 per 5 years), as was the prevalence of gastritis associated with Helicobacter pylori infection (87% of 1343 gastric biopsy samples in 1991).