A privately funded, limited admission, suburban animal shelter contacted Cornell University’s Maddie’s Shelter Medicine Program (MSMP) requesting assistance regarding a suspected panleukopenia outbreak. Many kittens under 16 weeks of age became progressively lethargic and died within 24 hours. Some showed signs of gastrointestinal disease prior to death. Feline panleukopenia is a contagious, often fatal disease caused by a parvovirus that is very resistant in the environment. Although the virus can affect any cat or kitten, panleukopenia more commonly affects unvaccinated cats living in close contact with other cats, such as in an animal shelter. This case report describes the recognition, diagnosis, and management of a feline panleukopenia outbreak at an animal shelter. The importance of vaccinating cats at intake, biosecurity, and proper sanitation of the facility is emphasized in preventing the spread of feline panleukopenia in the shelter environment.