Helicobacter pylori infection is highly prevalent, affecting approximately half of the world's population. While the majority of infected individuals are asymptomatic, H. pylori infection is associated with certain diseases, including peptic ulcers (either duodenal or gastric), gastritis, and 2 malignancies-gastric cancer and gastric mucosa-associated lymphoid tissue lymphoma. Many of the epidemiologic associations between these diseases and H. pylori infection have been further validated by treatment studies, which show that effective eradication therapy correlates with a decreased risk of disease. A variety of testing strategies are used to detect H. pylori infection. Serologic techniques are widely available and inexpensive, but they are no longer preferred as they have low sensitivities and specificities, and they may show a positive result for a long period following effective therapy. The remaining testing methods are divided into 2 categories: invasive tests (which require endoscopy) and noninvasive tests. Noninvasive test methods such as the urea breath test and stool antigen test have gained popularity due to their high sensitivities and specificities. Further, both of these methods may be used to confirm the absence of infection following eradication therapy. Due to the increasing incidence of treatment failure (caused in part by antibiotic resistance), post-treatment testing is recommended to confirm H. pylori eradication.