Background: Despite primary vaccination, infants under six months run a risk of infection with pertussis. Objective: To determine the impact of early postpartum maternal pertussis vaccination on protecting infants from the disease. Methods: All mothers (n=405) who gave birth to healthy term infants were educated on the cocoon strategy. The mothers who consented were immunized with the tetanus-diphtheria-acellular pertussis vaccine within the first three postpartum days. All infants received their pertussis vaccines according to the national schedule. The anti-pertussis IgG titers of infants of thirty vaccinated mothers were compared with those of thirty unvaccinated mothers. Results: The pertussis antibody levels in the infants of vaccinated mothers were significantly higher than those of unvaccinated mothers at the mean infant age of 5.6 ± 1.2 months. Only 6 infants of vaccinated mothers exhibited pertussis-like symptoms, none of whom had positive pertussis PCR. Seventeen infants of unvaccinated mothers had pertussis-like symptoms, and 4 tested positive for pertussis PCR. Conclusion: Our results showed that maternal pertussis vaccination, administered within the first three postpartum days, may protect infants against pertussis in their first ten months.