The aim of this study was to evaluate the effectiveness of regional hyperthermia combined with lamivudine (LAM) for treatment of chronic hepatitis B (CHB) and explore its possible mechanism. Forty CHB patients were randomly divided into the combination group (treated with regional hyperthermia and LAM ; n=17) and control group (treated with LAM alone ; n=23). Laboratory examinations were performed for hepatic function, hepatitis B virus (HBV) markers, and HBV DNA. Lymphocyte subpopulations including CD3+ (total T cells), CD4+CD8- (helper T cells) and CD4-CD8+ (cytotoxic T cells) were detected with flow cytometry. The side effects and tolerance were observed. Aspartate aminotransferase and HBV-DNA levels were significantly lower in the combination group than in the control group (P< 0.05). Hepatitis e antigen/antibody conversion rate was similar between the two groups, whereas the combination group had significantly higher rates of CD4+/CD8+ T cells than the control group (P< 0.05). Regional hyperthermia combined with LAM is superior to LAM alone for treatment of CHB, which may be achieved by enhancing cellular immune function.