Since the initial report 20 years ago by Marshall and Warren of an unidentified curved bacillus located on the gastric epithelium of patients with chronic active gastritis, the discovery of Helicobacter pylori and its association with a number of gastrointestinal diseases has revolutionized the field of gastroenterology. Although the association of H. pylori infection with peptic ulcer disease, chronic gastritis, mucosa-associated lymphoid tissue lymphoma, and gastric adenocarcinoma has been well documented over the past two decades, other areas remain less clear, including the role of H. pylori in gastropathy associated with nonsteroidal anti-inflammatory drugs, gastroesophageal reflux disease, and both uninvestigated and nonulcer dyspepsia. Although these areas still remain somewhat controversial, recent reports further clarify the role of H. pylori in these conditions. A review of the recent literature regarding H. pylori-associated diseases is presented along with recommendations for diagnosis and treatment of H. pylori infection.