Simple SummaryBirds of prey are important predators and scavengers at the top of the food chain, but their parasite diversity has not been well studied. The aim of this study was to identify several nematode specimens found in the gizzard of a booted eagle (Aquila pennata) during necropsy. Following morphological and molecular analysis, they were identified asPhysaloptera alata, a circumstance which represents the first report of this species in a booted eagle from Portugal. A new genetic sequence for this parasite is now available in GenBank for future research on birds of prey. This information is crucial for understanding the parasitological fauna of these birds in Portugal, as well as for wildlife rehabilitation centers, disease ecologists, and wildlife professionals to take appropriate measures in the event of parasitic disease.AbstractPhysalopteraspp. are parasitic nematodes that infect the gastrointestinal tracts of many carnivores and omnivores. Although they are distributed worldwide,Physalopteraspp. have not been studied in raptors in Portugal. In this study, we reportPhysaloptera alatain a booted eagle (Aquila pennata) in Portugal. Adult nematodes were discovered in the gizzard of a young booted eagle, and morphological features were consistent with those of the genusPhysaloptera. DNA was extracted and a PCR assay performed to amplify a region of the 18S small subunit of the ribosomal RNA gene and the cytochrome c oxidase subunit I gene. The resulting PCR products were Sanger-sequenced, and comparison with the available sequences in the GenBank database confirmed the initial morphological classification asPhysalopterasp. Phylogenetic analysis clustered the sequence within thePhysalopteragroup. The presence of this parasite in raptors from Portugal is of particular importance to wildlife rehabilitation centers, disease ecologists, and wildlife professionals. Furthermore, we produced a new genetic sequence and have added it to the GenBank database of parasites in birds of prey.