<p>Humans have long exploited the chondrichthyans, a lineage of jawed vertebrates characterized by a cartilaginous endoskeleton, and they remain an important fishery resource. However, fishing represents a major threat to cartilaginous fishes, especially given that their life history traits make them susceptible to fishing pressures. Indeed, oceanic shark populations have declined dramatically since the mid-twentieth century, with some chondrichthyans on the brink of extinction. While chondrichthyan-based pet food is prevalent in Taiwan, extensive food processing removes diagnostic morphological characters. This, combined with the use of generic product names, makes it difficult for customers to identify the species used in these products. Here, we authenticate through DNA barcoding 210 samples from 89 domestic and imported pet food products on the Taiwanese market. We successfully barcoded 207 of these samples, revealing sequences from chicken (<i>Gallus gallus</i>) and 28 chondrichthyan taxa (24 to species level and two each to genus and family level). Blue shark (<i>Prionace glauca</i>) was the most prevalent taxon, reflecting its highest catch biomass in Taiwan. None of the chondrichthyans we identified are on Taiwan’s Marine Protected Wildlife List, but some of them—<i>Rhynchobatus palpebratus</i> and <i>Sphyrna lewini</i>—are on CITES Appendix II and/or are threatened species according to the IUCN Red List. The use of generic names on pet food product labels likely results in a low mislabeling rate, but it also hinders customers from selecting products containing chondrichthyans of low conservation or health concern. Moreover, it creates a regulatory and or compliance issue for international trade, particularly for CITES listed taxa.</p>