The impact of adefovir dipivoxil (ADV) treatment on the immune system in patients with chronic hepatitis B (CHB) is unknown. The present study was designed to determine the expression of six cytokines, IL-2, IFN-γ, TNF-α, IL-4, IL-6 and IL-10, and their correlation with liver functions and clinical responses to ADV treatment. A total of 22 CHB patients were treated with ADV at a daily oral dose of 10 mg. Six cytokines, as well as AST, ALT and HBV DNA levels in blood samples were quantified prior to and following the treatment. A total of 10 healthy volunteers were enrolled as the control group. The six cytokines in CHB patients were significantly lower than in healthy individuals, and were increased significantly following 4, 12 and 24 weeks of ADV treatment. Although ALT, AST and HBV DNA were reduced following treatment, no correlation was found between these six cytokines and liver function or HBV DNA levels. The levels of the six cytokines in the group of patients with a complete clinical response were significantly higher than those in the group with a partial clinical response. ADV treatment increases the immunity of Th1/Th2 cells in CHB patients, and the increases in cytokines partly reflect the efficacy of the antiviral treatment.