BACKGROUND: Despite the availability of pediatric vaccines against pertussis ("whooping cough"), the disease is poorly controlled. Adolescents and adults with waning immunity, especially immediate family members, are responsible for 76%-83% of pertussis transmission to infants. Adolescent/adult tetanus, diphtheria, and acellular pertussis (Tdap) booster vaccines were licensed in the United States in 2005, but their use has been low and hospitals' implementation of immunization recommendations suboptimal. Efforts were implemented at two hospitals in Chicago to increase postpartum use of Tdap vaccine and to replace the tetanus and diphtheria toxoids (Td) booster with Tdap vaccine in emergency department (ED) settings. Postpartum Pertussis Vaccination Program at Prentice Women's Hospital: In the program's first 18 months (June 2008-November 2009) 9,540 doses of Tdap vaccine were administered to 78.87% of the postpartum patients. Children's Memorial Hospital: Tdap Use in Emergency Settings: In 2007, uptake of Tdap was slow. During 2008, of 43 ED patients receiving a tetanus toxoid-containing vaccine as part of wound management, 10 were given Tdap (20 had previously received a dose of Tdap vaccine). CONCLUSIONS: Hospital-based Tdap initiatives in postpartum and ED settings can be successfully implemented, provided that support is obtained not only from key decision makers at the hospital but also the health care providers who will be directly involved in implementing those initiatives. It is imperative that hospitals implement programs that increase the use of Tdap vaccine among postpartum women, in emergency settings, and among health care personnel.