AbstractLarval stages of pentastomids were collected from different organs of small mammals from the Peruvian Amazon. These parasitized mammals included: a western Amazonian oryzomys (Hylaeamys perenensis), an elegant oryzomys (Euryoryzomys nitidus), a lowland paca (Cuniculus paca), two kinkajous (Potos flavus), two silvery woolly monkeys (Lagothrix poeppigii) and a brown-mantled tamarin (Leontocebus fuscicollis). Pentastomids were found in the mesentery and parenchyma of the liver and lungs of these animals. All pentastomids were morphologically identified as nymphs ofPorocephalusspp. Only the nymphs collected from select animals (the western Amazonian oryzomys, the elegant oryzomys and the brown-mantled tamarin) were analysed molecularly. Molecular analysis was performed amplifying the mitochondrial cytochromecoxidase subunit I gene from select nymphs collected from the western Amazonian oryzomys, the elegant oryzomys and the brown-mantled tamarin. The nucleotide sequences exhibited 95.8–97.7% similarity between them. Also, these sequences showed an identity of 95.8–97.9% toPorocephalus crotali(GenBank accession numbers MG559647–MG559655). Molecular analysis indicated the presence of at least twoPorocephalusspecies. These findings represent the first record ofPorocephalusin these mammals, thus adding new intermediate hosts for this pentastomid genus. This work represents the first molecular data ofPorocephalusin a Neotropical climate.