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. Currently, HCV viral kinetics is considered to predict treatment response. Patients with rapid virologic response (RVR) are good predictors of SVR; those who fail to achieve RVR but achieve complete or partial early virologic response (cEVR or pEVR) should be put on prolonged therapy; those who fail to achieve EVR should be considered for treatment discontinuation because of low chance for SVR. Various host and viral factors, including race, gender, body weight, baseline viral load, and viral genotype, were considered to predict RVR. However, 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.