The clinical features and outcome of primary biliary cirrhosis (PBC) during long-term follow-up study (mean, 9 years; range, 1-20 years) was reviewed in 80 patients. Seventy per cent were asymptomatic at initial presentation. The mortality in the symptomatic group was 63%, compared with 20% in the asymptomatic group (p less than 0.001). The presence of hepatomegaly and histopathology consistent with stage 2-4 in asymptomatic cases was a prognostically ominous sign, as these patients often developed symptoms (p less than 0.001). The finding of histopathology consistent with stage 1, however, was correlated with an excellent prognosis with respect to both symptoms and mortality. Only 11% of these stage 1 patients became symptomatic, and none died (p less than 0.001). The mean age of symptomatic and asymptomatic patients did not differ. Moreover, the age distribution of asymptomatic patients with early histopathology and those patients with more advanced histopathology did not differ. This may indicate that asymptomatic PBC consists of subgroups with an active disease of various degrees.