This randomized, placebo-controlled clinical study evaluated the efficacy of lamivudine in 44 Vietnamese patients with histologically documented chronic hepatitis B for one-year. The patients were randomly assigned to receive 100 mg of lamivudine (22 patients) orally once daily or placebo (22 patients). The patients underwent liver biopsies before entering the study and after completing the assigned treatment regimen. At the end of therapy, the percentage of serum HBVDNA negativation was higher in the lamivudine group (86.4%) than in the control group (22% P<0.05). The rate of HBe/antiHBe seroconversion was statistically different between 2 groups (35.2% in the lamivudine group compared to 12.5% in the controls). 95.5% of the patients received lamivudine had normal alanine aminotransferase levels (versus 18.2% in the placebo). Median change in HAI score was >2 points of improvement versus placebo. Lamivudine is less side effects, safety, and favorable