Most liver biopsies performed today are for grading and staging of chronic viral hepatitis and steatohepatitis; there are uncommon indications for liver biopsy in the setting of acute hepatitis. Pathologists must have a broad knowledge of many forms of acute and chronic hepatitis, as well as their variations; these include viral hepatitis, autoimmune hepatitis, drug-induced hepatitis, metabolic diseases, and reactive hepatitis secondary to systemic disease processes. In this article, the authors review the pathological features of acute and chronic hepatitis.