Helicobacter pylori in the stomach is an etiological factor of gastritis and peptic ulcer. It is now considered that gastric cancer can be, at least in some cases, a late complication of H. pylori infection. In 123 consecutive endoscopic antral biopsies obtained from patients with the Okamoto Hospital, the specimens were subjected to the rapid urease test (RUT), histology (H&E stain), and culture, for the identification of H. pylori. The results of these methods were compared semi-quantitatively in order to evaluate these detection methods for identifying H. pylori. The results of these methods were found to agree well, with the Spearman's rank correlation coefficient between RUT and culture being 0.90 (P < 0.01) and that between histology and culture being 0.80 (P < 0.01). RUT is considered to be a very simple, sensitive, and highly specific test which enables the endoscopist to diagnose H. pylori infection.