Group B Streptococcus (GBS), or Streptococcus agalactiae, is the leading cause of early neonatal infections in infants. As part of prenatal prevention of this infection risk, the National Agency for Accreditation and Evaluation in Health (Anaes) has recommended since September 2001 that women be systematically screened for vaginal GBS carriage during high-risk obstetric situations and in late pregnancy, between 34 and 38 weeks of gestation (WG). The laboratory associated with the National Reference Center (CNR) for Streptococcus agalactiae has established a surveillance network for antibiotic resistance in this bacterium in France. This study reports the first evaluation by this network of the antibiotic susceptibility of S. agalactiae isolates obtained from vaginal screening samples at the end of pregnancy. The results will serve as a baseline for future assessments of the impact of routine antibiotic prophylaxis on GBS susceptibility. To this end, this survey will be repeated approximately every two years.