Combination therapy with peginterferon plus ribavirin has become the current standard of care for chronic hepatitis C (CHC) patients, with an overall sustained virologic response (SVR) rate of 54-63%. Based on the ample evidence, a 48-week course of peginterferon plus weight-based ribavirin therapy is widely recommended to treat HCV genotype 1 infection in different parts of the world. Despite the increased SVR rates with the improved medical therapies, about 25-50% and 10-20% of HCV genotype 1 and HCV genotype 2/3 patients may experience relapse after the cessation of therapy with undetectable HCV viremia at the end of treatment. Moreover, combination therapy is costly and may cause various adverse events. Therefore, individualized therapy based on outcome analysis should be adopted to save medical cost as well as to lessen inadequate treatment. Few studies are aimed to evaluate the host responses of micro RNA regulation during interferon-based therapy and its relationships to the overall treatment responses.