___________________________________________________________________________________________ *Corresponding author: Email: m_a_shadi@hotmail.com; British Journal of Medicine & Medical Research 3(4): 1109-1124, 2013 SCIENCEDOMAIN international www.sciencedomain.org Clinical, Endoscopic, Pathological and Serological Findings of Helicobacter pylori Infection in Saudi Patients with Upper Gastrointestinal Diseases Maha A. Abo-Shadi 1*, Tarek A. El-Shazly 2 and Mariam S. Al-Johani 3 1 Department Microbiology and Immunology, Al-Azhar University, Egypt 2 Department Internnal Medicine, Mansoura university, Egypt 3 Department of Biology, Taibah University, KSA. Authors’ contributions This work was carried out in collaboration between all authors. All the authors have made substantial contributions to the intellectual content of the paper. Author MAA planned and designed the study, wrote the protocol, participated in the interpretation of the results and analysis, drafted and critically revised the manuscript for important intellectual content and approval of the version to be published. Author TAE participated in planning and designing the study, sample collection and drafting of the manuscript. Author MSA collected the data and performed the practical laboratory activities. All authors also read and approved the final manuscript. Received 26 th November 2012 Accepted 17 th January 2013 Published 22 nd March 2013 ABSTRACT Background: The prevalence of Helicobacter pylori is typically higher in developing countries like Saudi Arabia. Aims: To estimate the prevalence of H. pylori among patients suffering from upper gastrointestinal (GI) symptoms, know the main risk factors leading to infection, and detect the clinical, endoscopic and pathological changes of the gastric mucosa of patients infected with H. pylori. Place and Duration of Study: This is a five-months prospective study conducted in King Fahd Hospital, Al-Madinah, Saudi Arabia. Methodology: H. pylori status in patients was determined by two biopsy based tests (histology and rapid urease test) as invasive tests and by a serological testing (ELISA Research Article