Wilson disease (WD) is an inherited disorder of copper metabolism. The resultant defective handling of copper results in toxic effects on the hepatocytes and increased copper in the circulation. Copper accumulates in other organ sites especially the central nervous system. WD occurs worldwide, usually between 5 and 35 years; a wider age range is now recognized. Clinical presentations are diverse and include combinations of hepatic, neurological, ophthalmic and psychiatric manifestations. Biochemical abnormalities such as serum ceruloplasmin and 24-h urinary copper excretion are important for the diagnosis but are not always abnormal in WD. They can overlap with non-WD causes. Patients may present with hepatic or neurological disease or combinations thereof. Approx. 50% of WD patients present with liver disease. Liver presentation is variable: asymptomatic abnormal liver tests, chronic hepatitis picture, cirrhosis, and acute liver failure. Similarly, the histology has several different patterns: mild nonspecific changes, steatosis or steatohepatitis, chronic hepatitis, and acute hepatitis with submassive or massive necrosis. None of these are specific for WD. Aids to the histologic diagnosis include special stains for copper and copper associated protein, and copper concentration in liver tissue. The biopsy is performed in the context of the clinical algorithms for the diagnosis of WD put forth by the clinical hepatology organizations such as the European Association for the Study of Liver Disease and the American Association for the Study of Liver Disease. The discovery of the responsible gene ATP7B has made the molecular diagnosis feasible through genetic testing and sequencing of the gene.