Recently, the relevance of Helicobacter pyroli (H. pylori) infection to atrophic gastritis and gastric cancer in has been elucidated. Therefore, to diagnose H. pylori infection is important for suspecting the existence of those diseases of the stomach. We investigated the relationships of the H. pylori IgG antibody to H. pylori infection, atrophic gastritisor various stomach lesions to understand the significance and usefulness of evaluating the antibody level in the annual multiphasic health check-up participants. The subjects in this study were 148 people (male: 93, female: 55, average age: 56.4) in Toride city, which is located in the suburb of Tokyo. They had visited our hospital for medical checkups. Eighty-seven subjects underwent upper gastric endoscopy and 55 (63%) tested positive for H. pylori IgG antibody and H. pylori infection was confirmed in 41 (75%). Although 32 subjects tested negative for the antibody, 8 cases (25%) was diagnosed with H. pylori infection. The frequencies of positive antibody in atrophic gastritis, erosion and ulcer, fundic gland polyp, hyperplastic foveolar polyp, adenoma and malignancy were 17%, 70%, 61%, 77%, 31%, 62%, 0% and 100%, respectively. On the other hand of 80 subjects were who underwent barium X-ray examination, 44 tested positive for the antibody (55%). The frequency of positive antibody in no lesion, depressed lesion, elevated lesion and malignant lesion were 61%, 59%, 36% and 100%, respectively. Taken together, H. pylori antibody was a good marker for H. pylori infection and the positive antibody indicated high frequencies of atrophic gastritis and malignancy. Therefore, advices to have participants who have a positive antibody should be strongly an endscopic examination stomach lesions.