Objectives: This study was designed to estimate the prevalence of Helicobacter Pylori infection in a healthy population in Korea and correlate between H. Pylori infection and serum pepsinogen levels as markers of gastritis and atrophic gastritis. Methods: We collected sera obtained form 104 children and 173 adult who had no gastrointestinal symptoms and measured specific IgG antibodies against H. Pylori by Bio-Rad G. A. P test. Serum pepsinogen 1 and 2 concentrations were determined by radioimmunoassay. Results: 1) The frequency of H. Pylori infection increased with age and was more than 80% over age 40. 2) Serum pepsinogen 1 and 2 concentrations in the healthy population were increased with age, while the serum pepsinogen 1/2 ratio decreased. 3) There were no significant statistical differences between the titre of specific IgG antibodies against H. Pylori and serum pepsinogens. Conclusion: The data from this study suggested that the prevalence of Helicobacter Pylori infection increased with age and serum pepsinogen levels were related to the presence or absence of H. Pylori infection. We conclude that H. Pylori infection is one of the factors which helps develop atrophic gastritis, the precursor lesion of gastric cancer.