The northern part of Sweden is sparsely populated and must be regarded as a rural region. An investigation into the incidence and prevalence of primary biliary cirrhosis was conducted and the course of the disease was followed. In total, 111 patients with primary biliary cirrhosis were identified for the 10-yr period 1973 to 1982 in the northern health region of Sweden. The mean annual incidence amounted to 13.3 per million and the point prevalence was 151 per million, which is the highest reported so far. There was a significantly higher prevalence in the most northern county of Sweden, both with respect to total number of primary biliary cirrhosis patients and symptomatic patients. Asymptomatic patients amounted to 37%. During the study period 25 patients out of the 111 died (23%), 14 as a direct consequence of the liver disease. Three patients died of primary hepatocellular carcinoma, one having an asymptomatic liver disease without cirrhosis. Primary biliary cirrhosis seems to be more common in Sweden, especially in the northern part, than it is elsewhere. A high frequency of extrahepatic symptoms (85%), mainly musculoskeletal, was recorded. These symptoms may lead to the first contact with the health service, rather than signs of liver disease. Thus, an increasing number of patients are diagnosed with asymptomatic liver disease, who must be followed to check for the eventual development of symptoms.