AIM: Urea breath test (UBT) is a non-invasive diagnostic test for detecting the presence of Helicobacterpylori(H pylori). In this study we evaluated the effect of anti-tuberculosis therapy on the results of 14C-UBT. METHODS: Patients, with the diagnosis of tuberculosis (TB) who had a positive UBT at the point of starting anti-TB therapy, were included. None had a history of peptic ulcer disease or had taken antibiotics, bismuth compounds and/or PPI in the previous month. 14C-UBT was repeated at the end of the second month and the end of treatment period and one month after completion of treatment course. RESULTS: Thirty-five patients (23 males) were enrolled. 14C-UBT was negative in all 35 patients (100%) at the end of the second month and remained negative in 30 cases (85.7%) at the end of the treatment course. One month after completion of treatment course, UBT remained negative in 13 patients (37.1%). CONCLUSION: Our report underscores the need for caution while interpreting urea breath test results in patients undergoing anti-TB therapy. Furthermore, the combination of drugs used in this study resulted in H pylori eradication in a minority of patients. AIM: Urea breath test (UBT) is a non-invasive diagnostic test for detecting the presence of Helicobacter pylori (H pylori). METHODS: Patients, had the history of peptic ulcer disease or had taken antibiotics, bismuth compounds and / or PPI in the previous month. 14C-UBT was repeated at the end of the second month and the end of treatment period and one month after completion of treatment course. RESULTS: Thirty-five patients (23 males) were enrolled. 14C-UBT was negative in all 35 patients ( 100%) at the end of the second month and remained negative in 30 patients (85.7%) at the end of the treatment course. One month after completion of treatment course, UBT remained negative in 13 patients (37.1%). CONCLUSION: Our report underscores the need for caution while interpreting urea br In addition, the combination of drugs used in this study resulted in H pylori eradication in a minority of patients.