Background and Aim: Chronic gastritis is one of the most common gastrointestinal disorders and detection of its etiology especially Helicobacter pylori and risk factors of malignancy (atrophy and intestinal metaplasia) is, to a great extent, based on histological assessment. Therefore, a system which could sustain good reproducibility in reporting observations is very important. Today, the most frequently used system for assessment and grading of chronic gastritis is the Updated Sydney System. The aim of this study was to find out inter-observer agreement on each criterion of this system (i.e reproducibility rate ).

  Materials and Methods: In this descriptive analytical study, 44 endoscopic gastric biopsy samples (with hematoxylin, eosin, and geimsa stains) were reviewed by two pathologists in turn. Each pathologist graded any of Sydney System criteria including chronic inflammation and H.P density level from 0-3 (absent, mild, moderate and severe) glandular atrophy and intestinal metaplasia from 0-1 (absence and presence). In addition, neutrophilic infiltration (activity of disease) was also graded from 0-3. Finally results of the observation were analaysed by means of McNemar statistical test and K coefficient

  Results: The most/best inter-observer agreement was found on intestinal metaplasia ( K =0.84) representing. Good interobserver agreement was observed on chronic inflammation ( K =0.67), H.P density (K=0.62) and neutrophilic infiltration (K=0. 68). For glandular atrophy, agreement was the least (K=0.32)

  Conclusion: Updated Sydney system is a useful system for the assessment and grading of chronic gastritis. In most cases there was good agreement between the observers. Reproducibility is evaluative differences in grading a specific feature and lack of standardized diagnostic criteria to charactrize its presence and degree.