Goals. Over the past twenty years, the existence of oral Helicobacter pylori (H. pylori) infection has been controversial and is still disputed. It proposes that living H. pylori do not exist in the oral cavity. However, the progressive loss of efficacy of standard eradication therapies has made the treatment of H. pylori more challenging than ever due to oral H. pylori infection. We conducted a study to explore the existence of oral H. pylori infection among 4321 adults. Procedures. A total 4321 adults (age range, 20-89 years old) comprising 2849 men and 1472 women were recruited by annual physical exam and evaluated using the saliva H. pylori antigen test (HPS) to diagnose oral H. pylori infection and the urea breath test (UBT) to diagnose stomach H. pylori infection. According to the classification on age grouping of World Health Organization, patients were divided into three age groups: A group, the young age subgroup (<45 years); B group, the middle age subgroup (45 to 59 years); C group, the old age subgroup (60-74 years) and D group, the elder subgroup (75-89 years). Results. We found the positive rate of oral H. pylori was 59.59% in the 95% confidence interval (CI) ranges on A group. The lowest positive rate of H. pylori in D group was 25.48% in the 95% confidence interval CI ranges. There was a statistically significant difference (p<0.001) between A, B, C, and D groups but no significant difference between men and women. Conclusion. HPS could identify oral H. pylori infection of individuals who have no risk for H. pylori gastric infection. The positive rate of oral H. pylori was 59.59% and this varies across different age groups. This information was not provided by UBT methods. It further identified that the prevalence of oral H. pylori infection is lower in the elder group that may be associated with fewer number of teeth.