Helicobacter pylori infection is basically acquired during infancy. H. pylori is associated with a great number of pathologies including gastritis, gastroduodenal peptic ulcer, gastric adenocarcinoma and MALT lymphoma. Its association with abdominal pain in children remains controversial. An association with iron deficiency anemia was recently described. The reference method for diagnosis still remains culture and histology of gastric biopsies realized during endoscopy. A few years ago, a lot of studies have shown the reliability of non-invasive tests (urea breath test 13C and the H. pylori stool antigen) for the diagnosis of the H. pylori infection in children. The treatment associating a proton pump inhibitor with two antibiotics (depending on the antimicrobial susceptibility when it's available) is recommended every time infection is proved. In children, the reinfection rate after H. pylori eradication is often higher than in adults. The eradication of H. pylori infection does not seem to produce the advent or the aggravation of gastro-oesophageal reflux oesophagitis. The eradication of this pathogen, in children as well as in adults, should theoretically lead to the disappearance of gastric cancer.