Seventy four asymptomatic carriers of hepatitis B surface antigen (HBsAg) were prospectively followed with biochemical liver function test and various hepatitis B viral markers over a period of 3 years. Two out of 74 subjects were found to have converted HBsAg positive into HBsAg negative during 3 years. A subject developed anti-HBs but another one did not develop anti-HBs. All of 74 subjects had anti-HBc and only a subject had IgM anti-HBc. Seventeen out of 72 subjects were found to carry HBeAg and 43 carried anti-HBe. Twelve subjects were found not to carry both HBeAg 8r anti-H Be. Aminotransferase were elevated in 8 out of 74 subjects. In contrast with 4 from 43 subjects with anti-HBe had elevated aminotransferase, 4 from 17 subjects with HBeAg were found to be elevated in aminotransferase level. We thought that 74 asymptomatic male HBsAg carriers had good prognosis over a period of 3 year observation.