Helicobacter pylori (H. pylori) infection can be diagnosed either by invasive techniques requiring endoscopy and biopsy (histological examination, culture, polymerase chain reaction) and or noninvasive techniques (urea breath test, serology, urine or blood, detection of H. pylori antigen in stool specimen). At present, no single test can be absolutely sufficient to detect the colonization by H. pylori, and a combination of above two tests is recommended if feasible. Because all the tests have their pitfalls and limitations, the choice of tests should depend on the clinical circumstances, the likelihood ratio of positive and negative tests, the cost-effectiveness of the testing strategy, and the availability of the tests. It is important to know which test in a certain clinical setting gives the best outcome. Some clinical circumstances warrant invasive studies, principally in patients with alarm symptoms (bleeding, weight loss, etc.) as well as older patients with new-onset dyspepsia. Endoscopy may also be advisable in patients who have failed eradication therapy and need culture to examine antimicrobial sensitivity testing to determine appropriate regimen. Recent Western studies have also demonstrated that a strategy of 'test and treat' for H. pylori in uninvestigated, young (<45 years), dyspeptic patients in primary care is safe and reduces the need for endoscopy. Therefore, it is necessary to hold a second consensus meeting for the diagnosis and treatment of H. pylori infection in Korea for the renewal of clinical guidelines in primary, secondary, and tertiary care based an evidence-based analysis.