SUMMARYIntroduction:Group B streptococcus (GBS) or Streptococcus agalactiae can colonize the gastrointestinal and genitourinary tracts and has been considered one of the most important risk factors for the development of neonatal disease. The present study evaluated the antimicrobial susceptibility of GBS isolates from pregnant women who were attended at a public health service in Northern Paraná, Brazil. Methods:A descriptive analytical cross-sectional study was performed with 544 pregnant women, at ≥ 35 weeks of gestation. One hundred and thirty-six GBS isolates from pregnant women were tested for antimicrobial susceptibility. Results:All of the GBS isolates showed susceptibility to the drug that is most frequently used for intrapartum prophylaxis: penicillin. Resistance to clindamycin and erythromycin was detected, thus decreasing the options of prophylaxis in women who are allergic to penicillin. Conclusions: Additional studies should be conducted to increase the knowledge of GBS sensitivity profile to antimicrobials in other health centers.