Helicobacter pylori is the main cause of most gastroduodenal diseases as dyspepsia, gastritis, peptic ulcer, gastric mucosa-associated lym- phoid tissue (MALT) lymphoma and gastric adenocarcinoma. In developing countries, it appears as a major public health. In Madagascar, the seroprevalence of H. pylori infection is 82% in adults. Diagnosing H. pylori infection is important because its eradication cures most of compli- cations and reduces the incidence of gastric cancer. Cag A, Vac A, OipA and DupA are currently the most described virulence factors of H. pylori. One of the major factors of the development of pangastritis and gastric cancer is the genetic polymorphism of interleukin-1. Diagnosis of H. pylori endoscopic (urease rapid test, histology and culture) and nonendoscopic methods (urea breath test, stool antigen test and antibody response). The choice of these tests depends on their availability and the distinction between tests used to establish a diagnosis of the infection and/or those used to confirm its eradication. In Madagascar, stool antigen test and histology are the two most interesting methods. Nowadays, eradication treatment of H. pylori encounters resistance phenomenon. Thus, treatment should be in accordance with the preva- lence of the resistance to clarithromycin and take in account the availability of Bismuth. In Madagascar, the prevalence of the resistance to clarithromycin is not known and Bismuth is not available, thus the first line therapy re- mains the standard treatment including proton pump inhibitors associated with two antibiotics (amoxicillin, clarithromycine, métronidazole). After failure of two lines of eradication treatment, treatment should be guided by antimicrobial susceptibility testing whenever possible.