Background: Infection with Helicobacter pylori is frequent in Chile, and a good test for its diagnosis ideally should be non-invasive, fast, easy and inexpensive. Aim: To report the use of an immunoassay test, that detects antigens of Helicobacter pylori in stools. Material and methods: One hundred and four patients that required an upper gastrointestinal endoscopy were studied. Stool samples were analyzed using an enzymatic immunoassay. These results were compared with those obtained with the urease test and microscopic examination of smears taken from biopsies obtained during the diagnostic endoscopy. Results: In 81 of 83 patients considered to have the infection according to the endoscopic tests, the antigen was also present in the stools. The test was negative in 16 of 21 patients considered to be without the infection. The resulting sensitivity and specificity for the immunoassay was thus 97.6 and 76.2% respectively, with positive and negative predictive values of 92.4 and 88.9%, respectively. Conclusions: These results are in agreement with those reported in the literature. Further studies are needed to define its usefulness in massive screening, follow up after antibiotic treatments or the detection of coccoid forms of Helicobacter pylori (Rev Méd Chile 2002; 130: 61-65)