To determine the life expectancy of patients with primary biliary cirrhosis, we analyzed survival data from 280 patients with either symptomatic (243) or asymptomatic (37) disease. Patients were followed for up to 19 years (mean, 6.9 years). The average length of survival was 11.9 years--nearly twice that reported in other studies. In contrast, over a 12-year period the survival of the asymptomatic patients after diagnosis did not differ from that of a control population matched for age and sex. Jaundice, weight loss, hepatomegaly, splenomegaly, and ascites were each associated with a poor prognosis. Prognosis also correlated with the histologic stages of hepatic fibrosis, cholestasis, and periportal-cell necrosis. A multivariate analysis of clinical features revealed that at the onset of disease, age, hepatomegaly, and elevated levels of serum bilirubin were independent discriminators of a poor prognosis. A histologic finding of fibrosis limited to portal areas improved this discrimination, correlating with prolonged survival. No other factors enchanced the prediction of risk.