BACKGROUND: Hemophiliacs are known to have higher risk of exposure of hepatitis virus and immunosuppression. The aim of this study is to investigate the positive rate of viral markers for hepatitis and anti-HIV and the changes of lymphocyte subpopulations in Hemophiliacs in Chonnam GwangJu area. METHODS: One hundred four patients who had visited to the Hemophilic Clinic, Chonnam University Hospital from 1999 to 2001 were enrolled. They were checked for type A, B, C hepatitis viral markers, anti-HIV and lymphocyte subpopulations. The prevalence of hepatitis and lymphocyte subpopulation were compared according to severity and age of hemophiliacs. RESULTS: Anti-HAV IgM, anti-HAV IgG, HBsAg, anti-HBs, anti-HCV were positive in 40%(22/55), 65.5%(66/101), 42.3%(42/97) of cases tested. Positivity of anti-HCV showed trends of increase according to the severity of hemophiliacs (P<0.01) and age(P<0.001). Previous infection of hepatitis B were increased according to age (P=0.01) but not to the severity (P=0.194). Positive rate of anti-HCV and previous infection of hepatitis B were significantly lower in young age group (10 years old) than in older age group (>11 years old) (P=0.003, P<0.001, respectively). Although all enrolled patients were negative for anti-HIV, absolute T and B cells counts were decreased in 71.6% and 14.9% of patients, respectively and inversion of CD4/CD8 ratio were found in 65.7%. But there were no statistical difference in not only decrease of T and B cells but also inversions of CD4/CD8 ratio according to age and severity. CONCLUSION: The number of hemophiliacs with previous history of hepatitis B virus infection and seropositivity of anti-HCV were increased according to the age and severity of hemophilia. Active vaccinations of hepatitis B may be required in hemophiliacs. The greater part of hemophiliacs showed decrease in T cell count and inverted CD4/CD8 ratio. The hemophiliacs need a cautiion for infection and follow up tests for immunologic function.