The progression of primary biliary cirrhosis was studied in 312 patients who were seen at the Mayo Clinic between January 1974 and May 1984. Follow-up was extended to April 30, 1988, by which time 140 of the patients had died and 29 had undergone orthotopic liver transplantation. These patients generated 1,945 patient visits that enabled us to study the change in the prognostic variables of primary biliary cirrhosis (age, bilirubin value, albumin value, prothrombin time and edema) from the time of referral. Also, using this database and the Cox proportional-hazards regression model, we developed an updated model for primary biliary cirrhosis that can be used to predict short-term survival at any time in the course of the disease. This model uses the values of the prognostic variables measured at the latest patient visit. Comparison of predicted survival from the update model and the natural history model of primary biliary cirrhosis showed that the updated model was superior to the original model for predicting short-term survival. This finding applied to both the Mayo Clinic patients and an independent set of 83 Dutch patients. The Mayo updated model is recommended for improving the accuracy of predictions of survival during the 2 yr after a patient visit.