Objective To investigate the changes in CD4+and CD8+T cell functions in patients with chronic hepatitis C in response to daclatasvir plus asunaprevir therapy. Methods A total of 21 HLA-A2-restricted patients with chronic hepatitis C virus ( HCV) genotype 1b infection were enrolled in this study. All patients were treated with daclatasvir plus asunaprevir for 24 weeks. Peripheral blood samples were collected at baseline, 4 and 24 weeks post-therapy. CD4+and CD8+T cells were sorted and purified. Cytokines secreted by CD4+T cells were measured by flow cytometry. CD8+T cells were co-cultured with HCV cell culture ( HCVcc)-infected Huh7. 5 cells in both direct and indirect contact co-culture systems. The cytolytic and non-cytolytic functions of CD8+T cells were analyzed by measuring the levels lactate dehy-drogenase and cytokines in the supernatants of cell culture. Results The virological and biochemical re-sponse rates were 71. 43% (15/21) and 77. 78% (14/18) at 4 weeks post-therapy, respectively. Both rates reached 100% at 24 weeks post-therapy. Secretion of IFN-γ, TNF-α and IL-17 by CD4+T cells was significantly enhanced at 4 and 24 weeks in response to daclatasvir plus asunaprevir therapy. In contrast, IL-10 secretion by CD4+T cells did not change notably post-therapy. However, no significant differences in cy-tokine secretion were found between patients with and without virological response at 4 weeks post-therapy. Daclatasvir plus asunaprevir therapy increased the percentage of dead cells in direct contact co-culture system of CD8+T cells and HCVcc-infected Huh7. 5 cells at 4 and 24 weeks post-therapy. However, it did not af-fect the cytotoxity of CD8+T cells in indirect contact co-culture system. Moreover, IFN-γ expression in both direct and indirect contact co-culture systems was significantly increased at 4 and 24 weeks post-therapy. There was also a notable increase in the expression of TNF-α in direct contact co-culture system, while no remarkable change in TNF-α expression was detected in indirect contact co-culture system. No significant differences in cytolytic and non-cytolytic activities of CD8+T cells were found between patients with virologi-cal and without virological response at 4 weeks post-therapy. Conclusion Daclatasvir plus asunaprevir ther-apy achieves high clinical cure rate in patients with chronic hepatitis C. Inhibition of HCV replication con-tributes to the improvement of CD4+and CD8+T cell functions.