BACKGROUND: Helicobacter pylori (H. pylori) is closely associated with gastritis, peptic ulcer and gastric carcinoma. We evaluated the reliability and usefulness of 73C-urea breath test (13C-UBT) for the detection of H. pylori infection and searched for the cut-off value of the test. METHOD : We investigated 45 patients, who underwent esophagoduodenoscopy with multiple biopsy specimens taken for culture, histology and rapid urease test, and 13C-UBT. Sensitivity and specificity of UBT were calculated against the combined biopsy-based test results. RESULT: Of 45 patients, 26 were found to be H. pylori-positive according to combined biopsy-based test-results. Sensitivity and specificity of the 13C-UBT were 100.0% and 89.5 %, respectively. CONCLUSION: The urea breath test provides a simple and reliable and noninvasive method of assessing HL pylori infection status.