Background: The aim of this study is to investigate the incidence, risk factor for antituberculoustreatment induced hepatotoxicity in patient with chronic viral hepatitis (CVH). Methods: The patients diagnosed with pulmonary and extrapulmonary tuberculosis(TB) from January 2005 to February 2014 were reviewed retrospectively. There were 83 patients in hepatitis B virus (HBV) infection (HBV group), 41 patients in hepatitis C virus (HCV) infection (HCV group), and 4 patients were both (HBV+HCV group).Patients without hepatitis virus infection were categorized to control group (n=251) from february 2013 to february 2014. Defi nition of drug induced hepatitis(DIH) is liver transaminase level exceeded 120IU/L with symptom of acute hepatitis or exceeded 200IU/L with without symptom, and transaminase level increased to >120 U/L when rechallenged the drug. Results: The incidence of drug induced hepatitis was signifi cantly higher in HCV (13/41 [31.7%] vs. 25/251 [10.8%] p=0.001) and HBV+HCV group (3/4 [75%] vs. 25/251 [10.8%], p=0.002) compared to control group. However, no significant differenceswere noted in incidence of DIH between HBV group and control group (11/83 [21.7%] vs. 25/251(10.8%) p=0.400). In all patients, risk factors of DIH were HCV infection, HBV+HCV co-infection, age, and baseline liver function abnormality. Conclusions: In patients with HCV infection, antituberculosis treatment induced hepatotoxicity occurred in 30%. Further prospective study on antitubertulosis treatment induced hepatotoxicity in patients with HCV infection may be warranted.