Gastrointestinal parasitism is one of the most common morbidities affecting shelter animals across the United States. High intake volumes, low staffing numbers, and limited resources within shelter systems encourage empirical deworming therapy during routine care. Empirical therapy may contribute to irresponsible resource management and anthelmintic resistance, reducing the reliability of anthelmintic products when treating diagnosed shelter animals, owned pets, and humans. The objective of this thesis is to evaluate common gastrointestinal parasite prevalence in cats and dogs entering Mississippi shelters and discuss the utility of pyrantel pamoate as an anthelmintic therapy in dogs. The first chapter discusses historical prevalence, pyrantel pamoate therapy, and potential development of resistance in companion animals. The second chapter evaluates regional prevalence in cats and dogs along with risk factors for parasitism. The last chapter assesses pyrantel pamoate’s efficacy and apparent parasite population response after an animal’s first week in the shelter.