100 consecutive British chronic carriers of hepatitis B surface antigen seen in a London teaching hospital are described. 77 were male homosexuals and only 19 had either symptoms or signs of chronic liver disease. 27 had normal liver function tests and 69 of the remaining patients had minimal changes, chronic persistent hepatitis, chronic active hepatitis, cirrhosis, or hepatocellular carcinoma diagnosed on liver biopsy. The 4 remaining patients did not have a biopsy but did have abnormal liver function tests. Chronic hepatitis B virus infection was an important cause of these conditions. Most patients showed no clinical, biochemical, or histological change during a mean follow-up period of 44 months, and only 9.7% spontaneously seroconverted from hepatitis B antigen positivity to become anti-hepatitis B e antibody carriers. Although the prognosis is good in the medium term, 7 patients died from hepatocellular carcinoma.