Background: Chronic gastritis is a chronic inflammation of the gastric mucosa and submucosa which is mostly caused by bacteria, mainly associated with H. pylori, causing damage or injury resulting in erosion of the stomach lining with clinical features of dyspepsia. The Sydney classification system is used to diagnose antrum-derived gastritis and corpus biopsy by assessing MN inflammation, PMN inflammation, glandular atrophy, intestinal metaplasia, and the presence of H. pylori bacteria. The Olga staging system is used to assess the degree of atrophy of glands that have a low risk and high risk of developing gastric malignancy. Objective: To determine the histomorphology of chronic gastritis using the Sydney system classification and the atrophy stage using the Olga system. Materials and Methods: Histomorphological re-observation was performed on chronic gastritis slides from antrum and corpus biopsy consisting of 114 cases. All characteristic data were obtained through medical record data and pathology archives. The statistical analysis was descriptive with a cross-sectional approach. Results: There were 114 cases. In the Sydney system classification, the most common histomorphology at antrum and corpus locations are grade 1 of MN inflammation, grade 0 of PMN inflammation, grade 0 of glandular atrophy, grade 0 of metaplasia intestine, and the presence of H. pylori is grade 0. In the assessment of the atrophy stage according to the Olga system, the most are stage 0 and the least is stage 3. Conclusion: The results of this study have various similarities with previous studies, but further investigation and research are needed for better results. Key words: Chronic gastritis, Sydney system, OLGA system, histomorphology