Pet-assisted therapy in the nursing home setting, as a vital component of the Eden Alternative or Human Habitat program, is gaining widespread recognition and implementation. Programs such as this help to improve the quality of life of nursing home residents by offsetting resident loneliness, helplessness, and boredom. However, use of companion animals (and, frequently, birds and fish) may be associated with the introduction of infectious entities that are normally uncommon in this setting (zoonosis). Examples include psittacosis, bartonellosis, toxocariasis, Capnocytophaga canimorsus, pasturellosis, Q fever, and leptospirosis, to name but a few. Hence vigilance for unusual clinical manifestations that may herald such diseases is necessary. In addition, prevention of such illnesses by routine veterinary screening of both resident and visiting companion animals is mandatory. Infection control policies and procedures geared toward management and prevention of zoonotic illnesses should be developed and implemented in all nursing homes offering pet-assisted therapy.