Objectives: The aim of the study is to present in detail the methods of sampling and detection methods of infection caused by the bacterium Helicobacter pylori and to discover the most effective method for bacterial diagnosis. Material and methods: Diagnostic methods of infection caused by Helicobacter pylori bacteria are based on the use of invasive and non-invasive methods. Invasive methods include histological analysis; bacterial culture; rapid urease test and PCR method, while non-invasive include a test for evidence of Helicobacter pylori antigen in stool; urea breath test and serological test. The Teaching Institute for Public Health of Split-Dalmatia County uses a non-invasive method of proving Helicobacter pylori antigen. Results: A positive result for presence of the Helicobacter pylori antigen is interpreted on the test cassette by the appearance of 2 red lines: control line and the line in the T region for test sample. Out of 9 samples tested at the Teaching Institute for Public Health of Split-Dalmatia County, one of them was positive for bacteria. Conclusion: Helicobacter pylori is a bacterium that is transmitted through contaminated food and water, by kissing, or fecal-oral route. Asymptomatic infection is possible. If infection is symptomatic, it causes various complaints such as bloating, burning sensation in the stomach, loss of appetite and vomiting. The histological method is still considered the gold standard. However, due to various factors that interfere with diagnosis, a non-invasive method of detecting Helicobacter pylori antigen in a stool sample is increasingly being used.