BACKGROUND Screening by serology for Helicobacter pylori in young dyspeptic patients has been shown to be effective in reducing demand for endoscopy. H. pylori has been implicated in the causation of gastric cancer and the reported seropositivity rate in patients with gastric cancer ranges from 69 to 94 per cent. The aim of this study was to assess the potential value of Helicobacter antibodies as a method of selecting dyspeptic patients over the age of 45 years for endoscopy. METHODS A retrospective comparison of the antibody status to H. pylori was made between 154 patients with gastric cancer and a sex- and date of birth-matched dyspeptic control group. Results from the former group were correlated with demographic data and tumour characteristics. RESULTS Significantly more patients with gastric cancer were seropositive than controls (77 versus 66 per cent). H. pylori was not related to the Laurén classification of the tumour. Tumour site was significant: body and antrum tumours were associated with Helicobacter whereas cardial tumours appeared to be unrelated. CONCLUSIONS Screening by antibody assays to H. pylori would miss more than 30 per cent of current gastric cancers. The increasing incidence of cardial cancer would cause this percentage to rise in the future.