At present, the clinical significance of Helicobacter pylori infection has been validly determined within the development of a diversity of gastroduodenal diseases, including chronic gastritis, gastroduodenal ulcer, MALT lymphoma, and gastric adenocarcinoma. The Expert Council's Maastricht IV consensus (2010) determining international standards for the diagnosis and treatment of H. pylori infection is that there is evidence that the latter may be associated with the development of a number of extragastroduodenal diseases (EGDDs) presented by iron-deficiency anemia of unspecified etiology, idiopathic thrombocytopenic purpura, and vitamin B12 deficiency. In these diseases, it is recommended that infection with H. pylori be diagnosed and, if the test is positive, this microorganism be eradicated. A large number of investigations have been recently conducted to examine the association of H. pylori infection with other EGDDs. This paper reviews theoretical and epidemiological data on the association of H. pylori with diseases of the cardiovascular (atherosclerosis, myocardial infarction) and central nervous (Alzheimer's disease, Parkinson's disease) systems, pancreas (autoimmune pancreatitis, pancreatic cancer), oncological (colonic adenomas, colorectal cancer, hepatocellular carcinoma), dermatological (chronic spontaneous urticaria), and other EGDDs. The review highlights the potential protective role of H. pylori in diseases with the atopic element of genesis and a complicated course of gastroesophageal reflux disease (Barrett's esophagus, esophageal adenocarcinoma).