Helicobacter pylorifrom the gastric and duodenal mucosa is an important clinical goal in the treatment of infected patients with peptic ulcer disease and other H pylori-associated conditions. Although several oral drug combination regimens are associated with eradication rates of approximately 85% in controlled trials, the success rate in patients infected with a resistant strain of H pyloriis closer to 75%. Resistance to metronidazole and clarithromycin, which are common components of combination treatment regimens, is of greatest concern. Reported rates of H pyloriresistance to various antibiotics vary considerably. In Canada, the data documenting H pylorisusceptibility are limited but suggest that resistance to these antibiotics varies geographically and within specific treatment groups. Although susceptibility testing is not a prerequisite for initial treatment of individual patients infected with H pylori, formal efforts to identify and monitor both the causes and prevalence of antibiotic resistance across Canada are a much needed step in the ongoing management of this important infection. Recommended treatment regimens may be useful, even for treating apparently resistant H pyloristrains. However, it is important to understand the mechanisms of the development of resistant strains to manage patients with treatment failure better.