In a prospective study of 180 HBsAg carriers, excluding patients from renal units or active drug users, excluding were followed by up to 8 years (mean 4 years). Four became HGsAg negative. SGPT was normal throughout in 70.6%. The rest had either intermittent, persistent or occasional elevations. The commonest pattern of SGPT abnormally was the intermittent one lasting weeks or months. Serial liver biopsies in carriers with normal SGPT showed mainly lobular infiltrates which reverted to normal. In carriers with elevated SGPT, portal infiltrates were found which persisted, compatible with a clinico-pathologic diagnosis of chronic persisting hepatitis (CPH). One patient progressed to liver cirrhosis and one developed CAH and cirrhosis. No patient developed hepatocellular carcinoma. HBsAg carriers can be divided into 2 groups: a) healthy, b) with asymptomatic chronic hepatitis B. Liver biopsy is recommended in group b, but not in group a.