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In total, 27 specimens of Parachaenichthys charcoti (Vaillant, 1906) caught off the South Shetland Islands were examined. Internal parasitic worms of 18 species and four unidentified larval forms were found: Acanthocephala (nine species, including five in the cystacanth stage), Digenea (seven species), Cestoda (three larval forms) and Nematoda (two species, including one in the larval stage, and one unidentified larval form). About 90% of the parasites utilized fishes as either intermediate or paratenic hosts. All species found at the adult stage occurred in the lumen of the alimentary tract. Metacanthocephalus johnstoni and diphyllobothriid plerocercoids are reported from P. charcoti for the first time. The level of infection increased in parallel with the fish size with a maximum of 1260 worms in one of the fish longer than 40 cm. Distinct differences of infections in two areas (fjord and open sea) were found. Five species, M. johnstoni, M. campbelli, Corynosoma arctocephali, C. shackletoni and Macvicaria georgiana, occurred only in Admiralty Bay, while Glomericirrus macrouri occurred only in Bransfield Strait. Of the remaining species, five, Aspersentis megarhynchus, Corynosoma hamanni, C. pseudohamanni, Genolinea bowersi and Ascarophis nototheniae, were 10 to 60 times more numerous in Admiralty Bay than in the open sea. A further three species, Metacanthocephalus dalmori, Lepidapedon garrardi and Elytrophalloides oatesi, were 2.5-9.5 times more numerous there. In contrast, Corynosoma bullosum and Lecithaster macrocotyle were 69 times and almost five times more numerous in the open sea, respectively. Levels of infections with Neolebouria antarctica, as well as with all worms in the larval stage, bilocular and trilocular cercoids, plerocercoids, Pseudoterranova decipiens and Contracaecum spp., were similar in both environments.