H. pylori infection is a significant global health concern. It cannot be diagnosed based solely on the patient's medical history and symptoms, and laboratory and imaging tests are often required to confirm the diagnosis. Both non-invasive and invasive methods are available for diagnosing H. pylori infection, including conventional and advanced detection techniques. It is not uncommon for patients to present with false-negative results due to the use of inadequate investigation methodologies, which prevents the adoption of appropriate clinical management. Thus, an analysis of the literature regarding the methods of diagnosis of H. pylori, with its advantages and disadvantages, is necessary. Publications in specialized scientific journals will undoubtedly contribute to facilitating access by professionals interested in the topic providing greater knowledge and potentially clinically useful guidance. In this review, the authors have sought to analyze and summarize the invasive and non-invasive methods, their applications, limitations, and the conditions that affect the sensitivity of the tests used for diagnosing H. pylori, an essential step for the successful treatment of this infection. It is essential to treat all patients infected with H. pylori. This represents a significant change in the approach, as previously treatment was recommended only for patients showing symptoms of infection. Therefore, it is crucial to understand the limitations of traditional diagnostic methods and help raise awareness among healthcare professionals about the latest advances in diagnosing this important bacterium.