A modified barrier system for maintaining Pasteurella multocida-free rabbits in an animal facility also housing Pasteurella multocida-infected rabbits was implemented. All research and laboratory animal technical personnel performed their duties involving non-infected rabbits prior to working with infected rabbits housed in separate rooms of the facility. Bacterial culture data involving mature rabbits indicated a 17% infection rate when Pasteurella-free rabbits were housed in a conventional manner for 3-6 months prior to institution of the modified barrier. No transmission of Pasteurella multocida from infected to non-infected rabbits housed in separate rooms was observed during 6 months of maintenance after initiation of the modified barrier system.