We describe a 27-year-old hepatitis B virus (HBV)-infected pregnant woman, with a history of miscarriage a year ago. The patient has been HBsAg and HBeAg positive for 20 years but has never been treated for HBV infection, because of stable elevated alanine aminotransferase (ALT) activity and high viral load. Treatment with tenofovir disoproxil was introduced in the 10th week of pregnancy and HBV DNA became undetectable. The clinical course of pregnancy was normal and the patient gave birth by caesarean section to a healthy child. At birth the newborn was HBsAg negative, after 3 months of follow-up is healthy, and evaluation of HBV status will be scheduled shortly. The decision to treat HBV infection during pregnancy should be individualized.