AIM:To evaluate the efficacy and safety of lamivudine treatment of chronic hepatitis B disease in pregnancy. METHODS:The study group was comprised of 38 chronic HBV patients who were diagnosed pregnant during lamivudine treatment and voluntary to continue the same therapy. The control group was from documented patient data in the literatures. We compared the following parameters with those of a control group: anti-HBV efficacy, complications of pregnancy (abortion, preterm birth, neonatal asphyxia, fetal death, and congenital anomaly), incidence of HBV-positive babies and developmental anomalies in pregnant women treated with lamivudine.