Objectives: To estimate the prevalence of rheumatoid factor(BF) positivity in adult Korean population and to investigate the association between viral hepatitis infection and rheumatoid factor positivity. Methods: The database from 21,907 subjects who visited general health screening center of Asan Medical Center during 1 year's period were surveyed. RF was tested using a commercial latex test kit(RapiTex® RF Test; Behringwerke). Results : 1) The prevalence of I4F was 2.9%(male 3.1%, female 2.7%) and increased along with the higher age groups. 2) The prevalence of HF in HBsAg(+) subjects was higher(13.3%) than that of RF in HBsAg(-) subjects(2.2%). 3) The prevalence of RF in anti-HCV(+) subjects was higher(6.1%) than that of BF in anti-HCV(-) subjects(2.8%). 4) HBsAg positivity was highly associated the presence of RF than age, anti-HCV, or abnormnl AST/ALT. Conclusion : The prevalence of RF in healthy Korean adults can be estimated as 3% and shows high association with hepatitis B and C virus infection.