Although the frequency of emergent drug-resistant strains of HCV in patients who failed to respond to simeprevir plus pegylated interferon (PEG-IFN) and ribavirin (RBV) decreased after cessation of the treatment, it is not clear whether or not the NS3-D168 variants affect the outcome of NS5A and NS3 inhibitor combination therapy. In this study, we investigated the relationship between the effect of daclatasvir plus asunaprevir treatment and the frequencies of NS3-D168 variants.