CTL together with anti-envelope Abs represent major effectors for viral clearance during hepatitis B virus (HBV) infection. The induction of strong cytotoxic and Ab responses against the envelope proteins after DNA-based immunization has been proposed as a promising therapeutic approach to mediate viral clearance in chronically infected patients. Here, we studied the CTL responses against previously described hepatitis B surface Ag (HBsAg)-HLA-A* 0201-restricted epitopes after DNA-based immunization in HLA-A* 0201 transgenic mice. The animal model used was Human Human D b (HHD) mice, which are deficient for mouse MHC class I molecules (β 2-microglobulin−/− D b−/−) and transgenic for a chimeric HLA-A* 0201/D b molecule covalently bound to the human β 2-microglobulin (HHD+/+). Immunization of these mice with a DNA vector encoding the small and the middle HBV envelope proteins carrying HBsAg induced CTL responses against several epitopes in each animal. This study performed on a large number of animals described dominant epitopes with specific CTL induced in all animals and others with a weaker frequency of recognition. These results confirmed the relevance of the HHD transgenic mouse model in the assessment of vaccine constructs for human use. Moreover, genetic immunization of HLA-A2 transgenic mice generates IFN-γ-secreting CD8+ T lymphocytes specific for endogenously processed peptides and with recognition specificities similar to those described during self-limited infection in humans. This suggests that responses induced by DNA immunization could have the same immune potential as those developing during natural HBV infection in human patients.