Little is known about parasites in wild mammals kept as pets. For this study, fecal and skin/fur samples and ectoparasites from 55 wild and pet mammals attended at a veterinary clinic were evaluated. Opossums (Didelphis albiventris and Didelphis aurita) were parasitized by helminths (Aspidodera sp., Cruzia tentaculata, Trichuris sp., Turgida turgida and Acanthocephala gen. sp.), screw-worm fly larvae (Cochliomyia hominivorax), ticks (Amblyomma dubitatum and Amblyomma sculptum) and fleas (Ctenocephalides felis). Hedgehogs (Atelerix albiventris) were parasitized by mites (Caparinia tripilis), capybaras (Hydrochoerus hydrochaeris) by ticks (A. dubitatum and A. sculptum), a ferret (Mustela putorius furo) by fleas (C. felis), an orange-spined hairy dwarf porcupine (Sphiggurus villosus) by screw-worm fly larvae (C. hominivorax) and another for ticks (Amblyomma longirostre). Overall, mites were found only in pet animals and helminths were found only in wild animals. Infestation by Caparinia tripilis was only found in animals with concomitant illness or stress. Cruzia tentaculata actively exited its opossum host by passing through the animal's anus as its clinical condition worsened.