Sixty-two of 66 (94%) Sylvirana supragrisea collected from 4 localities in Papua New Guinea harbored 1,137 endoparasies representing 15 known species and 1 new species. Proteocephalus papuensis n. sp. and the male of Desmognathiema papuensis Moravec and Sey, 1990, from the small intestine of the ranid frog Sylvirana supragrisea are described and illustrated. Proteocephalus papuensis is the second proteocephalid cestode to be described from New Guinea; it differs from P. niuginii in that it possesses a post-equatorial cirrus sac and 72–84 uterine pouches compared to an equatorial cirrus sac and 28–36 uterine pouches in P. niuginii. Desmognathiema papuensis is the third species assigned to the genus. It parasitizes ranid frogs of New Guinea, D. toyamai is known from an endemic Japanese frog, and D. nantahalaensis is a parasite of North American salamanders. In addition to these 2 species, gravid individuals of the nematodes Aplectana macintoshii, Cosmocerca novaaeguineae, Icosiella papuensis, Oswaldocruzia bakeri, Paracapillaria spratti, Pseudorictularia dipsarilis, Seuratascaris numidica and the acanthocephalan Acanthocephalus bufonis were found. Juvenile individuals of the nematode Abbreviata sp. (in cysts), unidentified cestode cysticerci, acanathocephalan cystacanths, and nymphs of a pentostome, Kirkicephalus sp., were also found. Sylvirana supragrisea represents a new host record for each of these parasites. Of the 1,137 endoparasite individuals, 638 (56%) were juvenile forms not capable of completing their life cycles in frogs. Of the 16 endoparasite species, no 2 collection sites had more than 7 species in common.