In 1990, LiPuma and colleagues1 described person-to-person transmission of Pseudomonas cepacia (now Burkholderia cepacia) between young adults with cystic fibrosis (CF) attending an educational program. One of the newly infected individuals had been previously in good health, but deteriorated rapidly and died within several months. This tragic case highlights the potential for catastrophic consequences from person-to-person transmission of bacterial pathogens in CF. This report and others from around the world that also described person-to-person transmission of B cepacia associated with acceleration of pulmonary disease and death led to the recommendation that people infected with B cepacia not attend Cystic Fibrosis Foundation (CF Foundation)-sponsored events. Reports describing person-to-person transmission of other more prevalent CF pathogens, most notably Pseudomonas aeruginosa, soon followed. In response, the CF Foundation published recommendations for infection prevention and control in 2003.2 Over the last 10 years, accumulating evidence has described further instances of person-to-person transmission of CF pathogens as well as poor clinical outcomes associated with transmission of certain strains of P aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), and Burkholderia.3 In response, the CF Foundation commissioned an update of the guidelines and invited public comment on a draft version. The period for public comment is now closed.