Parasites can be useful as biological tags for identifying fish stocks and tracking the movement of populations. King mackerel (Scomberomorus cavalla) is a predatory coastal pelagic teleost that occurs in tropical and subtropical waters in the western North Atlantic Ocean, including the Gulf of Mexico and Caribbean Sea. The species is important for commercial and recreational fisheries in the southeastern United States, with two populations currently recognized, one in the Atlantic and one in the Gulf of Mexico. King mackerel are the hosts for a diverse assemblage of parasites. The goal of this study was to determine if there were significant differences between the parasite communities of the two king mackerel populations and assess their potential use as biological tags. A total of 168 king mackerel were sampled from fishing tournaments in Florida, Alabama, and South Carolina, U.S.A., with a total of 22 individual parasite taxa identified, seven of which had not been previously described from this host species. Compositional differences were observed in the parasite communities of king mackerel from the Atlantic and Gulf of Mexico populations, as well as differences in abundance of several parasite taxa, suggesting that parasite abundance and community composition might be useful biological tags in this system.