OBJECTIVE: To compare the diagnostic usefulness of Helicobacter pylori (H.pylori) stool antigen test (HpSA) enzyme immunoassay (EIA) with the Campylobacter-like organism (CLO) test in Saudi patients with H.pylori associated dyspepsia. METHODS: Sixty consecutive adult Saudi patients suspected of H.pylori infection with dyspepsia attending the Gastroenterology Unit of the King Khalid National Guard Hospital, Jeddah, were recruited into the study. The study was carried out between 1st January and 30th June 2003. There were 25 males and 35 females. Their ages ranged from 19-72 years. Mean age was 39.6 years. At endoscopy diagnosis was made by taking gastric antrum mucosal biopsy for histology (Giemsa stain) and the CLO test was performed on a biopsy sample. A stool sample from each patient was sent to the Microbiology Department for HpSA EIA test. Helicobacter pylori status was determined by the positivity of the CLO test, the histology, or both. RESULTS: Both tests were positive in 26 specimens and negative in 21 patients. Discordant results were obtained in 13 specimens. Discordant results were resolved using the histology biopsy results. The sensitivity of the HpSA test was 88.6% and specificity 93.5%. The positive predictive value (PPV) of the HpSA test was 93.9%, while the negative predictive value (NPV) was 87.8%. The sensitivity of the CLO test was 87.8%, and specificity 92.5%, while PPV of the CLO test was 93.5% and NPV was 86.2%. CONCLUSION: The HpSA test is a useful and reliable test for the diagnosis of H.pylori infection. It is non-invasive, relatively cheap and convenient for the patient. It can be performed in any laboratory performing the enzyme-linked immunoabsorbent assay test. It is particularly suitable for developing countries where facilities for endoscopy are not readily available.