Helicobacter pylori is the most common infectious disease all over the world. Ten to twent parcent of the patients remain infected despite treatment with proton pump inhibitors (PPIs), amoxicillin and clarithromycin. We compared PPI, bismuth, tetracycline and metronidazole with ranitidine bismuth citrate, tetracycline and metronidazole in cases resistant to PPIs-based triple therapies. Methods: The study included 52 patients who underwent a triple therapy with PPI, clarithromycin and amoxicillin for 14 days between September 2001 and December 2002, and were found to be resistant to the therapy. They were randomized to take ranitidine bismuth citrate (Rb) 400 mg twice a day, tetracycline (T) 1 g twice a day and metronidazole (M) 500 mg three times a day for 14 days (RbTM), or ranitidine bismuth citrate (Rb) 400 mg twice a day for 14 days and azithromycin (A) 500 mg once a day for 7 days (RbA). Four weeks after the treatment, endoscopies were repeated, and patients were assessed with respect to changes in symptoms. When H. pylori was negative on histological analysis and urease test, eradication was achieved. Results: A total of 52 patients, 32 females and 20 males with a mean age of 49±12 years, were included in the study. Eradication was achieved in 15 (28%) out of 52 patients in total. There was a significant difference between RbA and RbTM groups (p=0.01). In fact, H. pylori was eradicated in 3 (12%) out of 25 patients in the RbA group, whereas it was eradicated in 12 (44.4%) out of 27 patients in the RbTM group. Symptom scores significantly improved in both groups after the treatment, though there was not a significant difference between the groups (p=0.705). Conclusions: Triple therapy including azithromycin does not seem to be a good choice in cases resistant to the first line therapies; however, a similarly lower rate of eradication was achieved with the quadruple therapy proposed. Therefore, different treatment schemes should be applied in resistant patients, and further studies are needed as well.