Sustained abnormal liver function is closely associated with chronic hepatitis in Korea with high prevalence of hepatitis B infection. Follow up about AST and ALT on 839 adults(male 727, female 112) was executed with interval of at least 6 months for 2 years to evaluate the factors contribute to the progression of chronic hepatitis. HBsAg, HBsAb, anti-HCV, body mass index(BMI), total cholesterol, fasting blood sugar(FBS), Clonorchis sinensis in stool(Cs), fatty liver on abdominal sonogram and alcohol habit were also checked. We defined abnormal liver function as both of AST 35 U/L and ALT 50 U/L. As the result of first time liver function test(LFT), the frequency of abnormal liver function was 13.6%(114/839). The positive rate of HBsAg and HBsAb was 7.0% and 73.9%, respectively, and the positive rate of anti-HCV and Cs was 0.7% and 1.3%. As the result of the follow up, 6.2%(52/839) in total has a tendency of chronic hepatitis with sustained abnormal LFT. Among abnormal LFT, 45.6%(52/114) was sustained LFT abnormality, and 12.8%(93/725) was aggravated LFT abnormality from normal LFT at the first check. From these results, male and hepatitis B infection were evaluated as important factors for the progression of chronic hepatitis. HBsAb considered that has a protective effect to the progression of chronic hepatitis. Therefore, even though no symptoms or sign, periodic examination for hepatitis B marker and LFT is important to control the chronic hepatitis, especially for male. Furthermore, because only 25%(13/52) of sustained abnormal LFT was HBsAg positive, it suggests that further study for evaluating the factors except hepatitis B infection would be needed for the control of chronic hepatitis.