STUDY/PRINCIPLES: Antibiotic prophylaxis of Group B Streptococcus (GBS) positive women during labour reduces the risk of early-onset neonatal sepsis. Penicillin is the first choice, and clindamycin and erythromycin are second choices for penicillin-allergic women. Resistance to these antibiotics is rising. The aims of this study were to evaluate the rates of clindamycin and erythromycin resistance among GBS-positive isolates cultures from pregnant women in the University Hospital of Geneva and to evaluate the legitimacy of new Centres for Disease Control and Prevention (CDC) recommendations for our context.