BACKGROUND: The association of dietary habits and Helicobacter pylori infection with early gastric cancer is still unclear. METHODS: A hospital-based case-control study was conducted in Korea. Sixty-nine patients were newly diagnosed as having early gastric cancer at the Division of Gastroenterology, Asan Medical Center, and 199 healthy subjects who visited the Health Promotion Center of the this same hospital for annual health examinations were selected as controls. Helicobacter pylori infection status was assayed by ELISA, and information for dietary habits was obtained by interview using a semi-quantitative food frequency questionnaires. Preference for salty taste was also evaluated using a sensitive test. RESULTS: H. pylori seropositivity was observed in 88% of cases, as compared with 75% of controls (OR=5.3, 95% confidence interval:1.7-16.5). Adaptive salt concentration was significantly and positively associated with early gastric cancer risk (p<0.01). Decreased risks of early gastric cancer were observed in association with intakes of clear broth, raw vegetables, fruits, fruit or vegetable juices, and soybean curds. On the other hand, a high intake of salt-fermented fish and kimchi were associated with an elevated risk of early gastric cancer. Subjects with positive H. pylori infection and a high salty prefer- ence had a 10-fold higher risk of early gastric cancer than subjects without H. pylori infection and with a low salty preference (p for interaction = 0.047). CONCLUSION: Some dietary factors and H. pylori infection are significantly associated with early gastric cancer. In particular, high-salty diets may enhance the effect of H. pylori infection in gastric car- cinogenesis. J Epidemiol 2003;13:162-168.