Animal hoarding is an under-recognized problem that exists in most communities and adversely impacts the health, welfare, and safety of humans, animals, and the environment. These guidelines address public health and worker safety concerns in handling situations where animal hoarding or other dense concentrations of animals have caused unhealthy and unsafe conditions. Because animal hoarding situations are often complex, a full response is likely to be prolonged and require a cross-jurisdictional multiagency effort. Each animal hoarding case has unique circumstances related to the types and numbers of animals involved, the physical structure(s) where they are being kept, and the health status of the animals, among other factors that must be taken into account in planning a response. Some general public health considerations and associated recommendations for personal protective equipment use are presented that apply to all cases, however.