Feline upper respiratory tract diseases (cat “colds”) are a devastating illness in animal shelters and other multiple cat environments. The viruses that cause upper respiratory infections (URI), like those that cause human colds, are always present in cat populations. When large numbers of cats and kittens are housed together disease spreads easily. Although URIs are treatable, affected cats in shelters are less adoptable and serve as a source or re-infection for other cats. Therefore, they are often euthanized to make room for healthy cats. Shelters attempt to minimize the incidence of URI through management practices, vaccination programs, stress reduction, hygiene and good nutrition for example. Few studies have been conducted to evaluate the effectiveness of these approaches. In order to evaluate the various approaches to minimizing the incidence of URI, we first need to establish baseline data describing upper respiratory disease in shelters, which is the central objective of this study. By determining the actual incidence of URI and identifying factors that are associated with risk of URI, we can develop strategies to minimize its occurrence and study the impact of these strategies. This information will then allow us to help shelters, catteries and other multi-cat households to take successful steps toward creating a healthier shelter environment for cats.