Helicobacter pylori infection is the most common infection of the human species, with developing countries displaying a marked disadvantage in contrast to developing countries. While H. pylori infection is asymptomatic in most infected individuals, it is intimately related to malignant diseases of the stomach, such as gastric cancer and gastric MALT lymphoma, as well as benign diseases, for example chronic gastritis and duodenal and gastric peptic ulcers. Since the discovery that gastric mucosa could be colonized by bacteria, evidence of greater than 50 extragastric manifestations has been reported, linking H. pylori infection and the development of diseases associated with cardiology, dermatology, endocrinology, obstetrics and gynecology, hematology, pneumology, neurology, odontology, ophthalmology, otorhinolaryngology, and pediatrics. This chapter presents the extragastric manifestations of H. pylori infection expressed through hematologic diseases; particularly those included in the international consensus, and discusses guidelines for the management of H. pylori infection, such as iron deficiency, vitamin B 12 (cobalamin) deficiency, and immune thrombocytopenia. Other manifestations reviewed include immune neutropenia, antiphospholipid syndrome, and plasma cell dyscrasias, such us monoclonal gammopathy of undetermined significance, multiple myeloma, and Henoch-Schönlein purpura.