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Background and Objective: Most of the diagnostic methods of Helicobacter Pylori infection are invasive and time consuming. This study compared salivary IgG with serum IgG in diagnosis of H.pylori infection in dyspeptic patients in order to search for a non-invasive, cheaper and more tolerable method. Materials and Methods: In a cross-sectional diagnostic study, during one year (Feb 2002-Feb 2003) 200 consecutive patients (Age range 11-83) referring to Imam Khomeini Hospital. For upper gastroduodenal endoscopy were recruited. Three biopsy specimens were obtained from antrum and body of the stomach and three from duodenum. Histological examination (Hematoxylin-Eosin and Gimsa), rapid urease test and culture were performed. Saliva and serum were obtained before endoscopy and IgG antibody level were determined by ELIZA using Randim Kit (Roma, Italy). Sensitivity, specificity, positive and negative predictive values were evaluated by SPSS soft ware. Results: Salivary IgG correctly identified 120 out of 146 H.pylori infected patients (82%). Salivary IgG assay showed high sensitivity in the detection of H.pylori infected patients (88.2%). Specificity and positive predictive value of Salivary IgG were higher than those of serum (84.4% versus 83.1% and 92.3% versus 91.9%). Conclusion: Salivary IgG assay can be used as an alternative to other non-invasive methods for screening of H.pylori infected patients.