BACKGROUND/AIMS: Helicobacter pylori (H. pylori) treatments fail at least in 10-20% of patients. However, retreatment strategies after failure of initial treatment have not been established. This study was conducted to evaluate the eradication rate of retreatment choices. METHODS: Twenty-seven peptic ulcer patients who were retreated with OAC (omeprazole + amoxicillin + clarithromycin) or BMT (bismuth + metronidazole + tetracycline) after failure of BMT or OAC were included. Quadruple therapy (omeprazole + BMT) was also tried after failure of two successive triple therapies. Furthermore, the effect of resistance of metronidazole or clarithromycin on the eradication of H. pylori was evaluated. RESULTS: Among 13 patients who were retreated with OAC after failure of BMT regimen, H. pylori was eradicated in 10 patients (76.9%). Among 14 patients retreated with BMT after failure of OAC regimen, H. pylori was eradicated in 11 patients (78.6%). Resistance of H. pylori to metronidazole or clarithromycin decreased the efficacy of BMT or OAC, respectively. CONCLUSIONS: Eradication regimen should be decided considering the resistance to H. pylori. However, in case of unknown state of resistance, OAC can be chosen if BMT fails. Similarly, BMT can be tried in cases that OAC therapy failed. After failures of both triple therapies, quadruple therapy can be tried as the next step.