Hepatitis C virus (HCV) is one of the main causes of liver disease. 1~2% of the Korean people has been reported to be infected by HCV. Although HCV is less infectious than hepatitis B virus (HBV), it is more prone to develop chronic infection (~ 80%) which may link to cirrhosis and hepatocellular carcinogenesis. In addition, prevalence of hepatitis caused by HCV infection is gradually increased every year in Korea. Recently, a large number of clinical trials using direct-acting antiviral (DAA) drugs have been shown efficient therapeutic results for chronic HCV infections and some of them are on the market. However, there is still a concern on viral evasion to the DAAs and the effective mechanisms of immunological clearance of HCV remains to be elucidated. Here, we introduce the recent findings on the role of Th17-Treg axis which may play a critical role of the viral pathogenesis and/or immunological defense against HCV infection. The underlying regulatory mechanisms of Th17-Treg axis might be a potential candidate for the better control of HCV chronic infections.