We aimed to investigate the influence of regulatory T cells including CD4+CD25+, CD8+CD28- and hepatitis B virus (HBV) genotype on sustained virological response and tolerance of nucleoside drugs. One hundred and thirty-seven patients were enrolled. Lamivudine was administered to 84 patients. Entecavir was administered to the other 53 patients. Before treatment, biochemical tests, HBV DNA load, HBV serum level, HBV genotype, PB CD3+, CD4+, CD8+, CD4+CD25+/CD3+, and CD8+CD28-/CD3+ frequencies were measured. Based on HBV DNA loads after 4 weeks of therapy, patients were divided into response group and suboptimal response group. The lamivudine group received treatment continuously, and then patients were categorized into non-resistance group and resistance group. Compared with the suboptimal response and resistance groups for lamivudine, CD4+CD25+/CD3+ levels were higher in the response and non-resistance groups (t=4.372, P=0.046; t=7.262, P=0.017). In the non-resistance group, CD8+CD28-/CD3+ frequency was lower than in the resistance group (t=5.527, P=0.037). Virus load and hepatitis B E antigen (HBeAg)-positive rate were significantly lower than in the response and resistance group (t=2.164, P=0.038; X 2=4.239, P=0.040; t=2.015, P=0.044; X 2=16.2, P=0.000). Incidence of drug resistance was high in patients with virogene type C. For the virological response to entecavir, CD8+CD28-/CD3+ level was significantly lower than that of the suboptimal response group (t=6.283, P=0.036). Response and suboptimal response groups were compared in CD3+, CD4+, CD8+, CD4+CD25+/CD3+ and virus genotype, and differences were not statistically significant (P>0.05). Baseline regulatory T cells including CD4+CD25+/CD3+ and CD8+CD28-/CD3+ frequencies have a relationship with the incidence of rapid virological response and the resistance to nucleoside drugs. Patients with HBV genotype C receiving lamivudine more often underwent drug resistance. Antiviral efficacy and the resistance to lamivudine were closely correlated with baseline factors; the same cannot be found for entecavir.