H.C. Lai 1 , S.W. Lai 1 , K.F. Liao 1 , C.S. Liu 1 , T. Lin 1 , C.C. Lin 1 1 China Medical University Hospital, Taichung, Taiwan Background: In 2007, chronic liver disease was the seventh leading cause of death in Taiwan. Hepatitis B and hepatitis C are two major causes of chronic liver disease in Taiwan. The purpose was to investigate the seroepidemiology of hepatitis B surface antigen (HBsAg) and hepatitis C virus (HCV) antibody in Taiwan. Method: This was a hospital-based cross-sectional study. We analyzed viral hepatitis data from 2695 subjects who received health checkups at one medical center in Taichung from 2003 to 2004. All subjects were divided into three age groups, including 20-39, 40-64 and 65. This study emphasized the prevalence of HBsAg and HCV antibody by gender and age. The statistical analysis was performed by t test and 2 . Result: There were 1526 men (56.6%) and 1169 women (43.4%). The mean age was 49.2 (standard deviation 12.2, range 20-84). The overall prevalence of HBsAg was 14.7%, with statistically significant difference(SSD) between gender (17.4% for men vs 11.2% for women, p <0.001). The prevalence of HBsAg was decreased with age in men, with SSD (p <0.001), and also decreased in women, without SSD (p =0.08). The overall prevalence of HCV antibody was 5.2%, without SSD between gender (4.8% for men vs 5.7% for women, p =0.272). The prevalence of HCV antibody was increased with age both in men and in women, with SSD (p <0.001). Conclusion: We hope this study can provide the epidemiological data for further studies of hepatitis B and hepatitis C virus infection in Taiwan.