Biopsies of gastric mucosa, obtained at endoscopy, are common in routine pathology practice. The material ranges from single random biopsies of macroscopically normal or near-normal mucosa to detailed series mapping processes such as atrophic gastritis. In practice, the majority of cases will fall into the normal/near-normal mucosa, reactive gastritis, or Helicobacter pylori-associated gastritis categories. In this chapter, a practical, systematic approach to reporting gastric biopsies is emphasised to ensure that the pathology report assists in patient management. Three common systems for classification of gastritis – Sydney, ICD-10, Kyoto – are summarised and the key features required in the pathology report discussed. An approach to the differential diagnosis of some commonly encountered histological findings/patterns of mucosal injury, including atrophic gastritis, lymphocytic gastritis, and ‘granulomas’, is provided. There is discussion of the appropriate use of histochemistry/immunohistochemistry in gastric biopsies, noting that ‘routine specials’ add little to the assessment of H&E sections in most cases. Finally, the need for accurate clinical information (including endoscopic appearances, sites of biopsy, medical history and current/previous medications) to aid interpretation of the morphological findings and of the results of ancillary investigations is considered.