Wilson disease is an inherited, autosomal recessive, copper accumulation and toxicity disorder that affects about 30 individuals per million. This rare disease is caused by mutations in the gene encoding a copper-transporting P-type ATPase, which is important for copper excretion into bile, leading to copper accumulation in the liver. Toxic copper concentrations can also be found in the brain and kidney, and clinical phenotypes include hepatic, haemolytic, neurologic and psychiatric diseases. Diagnosis is based on the combination of clinical features and findings such as increased urinary copper excretion, reduced levels of serum ceruloplasmin, high concentrations of copper in liver tissues and Kayser-Fleischer rings. Genetic studies are also becoming available for clinical use, but the utility of direct mutation analysis is limited. Wilson disease can be treated, and early diagnosis is essential: the goal of therapy is to reduce copper accumulation either by enhancing its urinary excretion or by decreasing its intestinal absorption. Medical therapies include penicillamine, trientine, zinc and tetrathiomolibdate. Liver transplantation is a relatively successful treatment option when medical therapy fails or in case of acute liver failure, even though it is also characterized by short- and long-term complications.