Currently available evidence is insufficient to classify PBC and AIC as separate diseases. The ultimate answer to the question of whether AIC, defined as AMA-negative PBC with ANA or SMA, is a disease distinct from AMA-positive PBC with or without ANA will require a detailed comparison of etiologic factors and pathogenetic mechanisms, once they are elucidated. It is intriguing to consider the suggestion of Heathcote that the term autoimmune cholangitis be adopted to describe PBC with or without detectable AMA. However, it is improbable that the venerable term PBC will be supplanted. Hepatologists will probably continue to use the terms AIC and AMA-negative PBC interchangeably, with little risk of being misunderstood.