Background Anti-parietal cell antibody is found in patients with Helicobacter pylori-positive gastritis and is related to atrophic gastritis and gastric carcinoma. Aim To identify the characteristics of patients at high-risk for gastric carcinoma in terms of anti-parietal cell antibody and serum pepsinogen. Patients and methods Subjects were 92 H. pylori-positive patients (54 men, 38 women; mean age, 57.9 years; range, 15–88 years). The serum concentrations of pepsinogen I and II were determined by radioimmunoassay, and the presence of anti-parietal cell antibody was assessed by enzyme-linked immunosorbent assay. Degrees of inflammation and atrophy in the corpus of the stomach were evaluated histologically. Results Patients were classified into four groups according to anti-parietal cell antibody status and pepsinogen I/II ratio. Anti-parietal cell antibody-negative/pepsinogen I/II-low patients had the highest risk for gastric carcinoma (prevalence of gastric carcinoma: 7/13 = 53.8%, odds ratio = 7.6, 95% confidence interval, 1.2–48.0). Anti-parietal cell antibody titre was high when inflammation in the corpus was severe ( p = 0.06) and significantly low when atrophy in the corpus was severe ( p = 0.01). Conclusion Our results showed that patients with a negative anti-parietal cell antibody titre and low pepsinogen I/II ratio are at high-risk for gastric carcinoma.