The aim of this study was to determine the prevalence of antimicrobial resistance amongst Helicobacter pylori isolates cultured from gastric biopsies taken during routine endoscopies at the American University of Beirut Medical Center in Lebanon. Fifty-four consecutively recovered H. pylori isolates were tested against metronidazole, clarithromycin, tetracycline and amoxycillin using the epsilometer test. Resistance to metronidazole (MIC > 8 mg/l) was found in 29.5% of the isolates while resistance to clarithromycin (MIC > or =0.25 mg/l) and tetracycline (MIC > or =4 mg/l) was low (4 and 2%, respectively). All isolates were susceptible to amoxycillin (MIC < or =8 mg/l). These findings are comparable with those reported from Europe and the United States. The prevalence of metronidazole resistance in our study was lower than that from other parts of the Middle East and the developing world.