To discuss exhaustively: clinical, serological and pathologic aspects of primary biliary cirrhosis (CBP); recent advantages in the knowledge of the disease's pathogenesis, therapeutical approaches that still appear less preferable than liver transplantation.We reviewed the most important recent studios on CBP.More than 90% of patients have antimitochondrial antibodies, so that CBP can be considered an autoimmune disease. Inciting agents could be either PDC E2-like or MHC molecules. An autoaggressive mechanism against biliary ducts could be the following: the neo-antigen on the surface of biliary tract cells could be the target for the immunological damage; anti PDC-E2 antimitochondrial antibodies could be secondary to the cellular damage and to the release of mitochondrial enzymes.In primary biliary cirrhosis, several circumstances (specificity of biliary-ductal destruction, lymphocyte infiltration of portal tract, abnormal expression of HLA-DR on surface of biliary epithelium cells) suggest that the epithelial cells of intrahepatic biliary ducts are the target of a severe and isolated immune response. The identification of the E2-like PDC antigen is a significant achievement in the knowledge of the pathogenetic process. On this basis, it is now to investigate possible genetic markers of risk and to clarify the role of T cells in the immunopathogenesis of the illness. The only effective treatment for CBP is liver transplantation.