Context.-A variety of inflammatory disorders may affect the colon, with widely differing clinical outcomes and management. These conditions encompass a spectrum of acute and chronic conditions.Objective.-Review the pathology of the major colitides and highlight the most diagnostically useful features.Data Sources.-Review of recent literature supplemented with personal experience in the field of gastrointestinal pathology.Conclusions.-The etiologies associated with the various types of colitis are diverse and the range of histologic changes is somewhat limited. Nevertheless, the combination of clinical and endoscopic data coupled with histopathology allows for accurate classification in the majority of cases.