The prognosis and natural history of primary biliary cirrhosis (PBC) have improved significantly during the last few decades. Patients are diagnosed at earlier stages, are more likely to be asymptomatic at diagnosis, and are more likely to receive medical treatment. The survival of asymptomatic patients is longer than the median survival of symptomatic patients. The natural history of PBC has been assessed in the presence of effective therapy, ursodeoxycholic acid (UDCA). Evidence suggests that UDCA delays histological progression in PBC and decreases the risk of development of esophageal varices. Survival of UDCA-treated patients is better than that of untreated patients and also is better than that predicted by the Mayo model. For patients in early stages of PBC, UDCA treatment may normalize survival. However, patients with stage III and IV PBC do not respond as well to UDCA. Therefore, there is a continued need for additional treatment in patients with advanced disease.