Autoimmune liver disorders are inflammatory liver diseases characterised histologically by a dense mononuclear cell infiltrate in the portal tract and serologically by the presence of non-organ and liver specific autoantibodies and increased levels of immunoglobulin G (IgG), in the absence of a known etiology. They usually respond to immunosuppressive treatment, which should be instituted as soon as diagnosis is made. The onset is variable and often mimics acute hepatitis. The previously accepted requirement of six month duration of symptoms before a diagnosis of autoimmune disease could be made has been abandoned.