Paragonimus peruvians sp.n was described from two cats captured in La Asunción and El Guayo, Cajamarca, Peru. The new species is allied to P. mexicanus Miyazaki et Ishii, 1968 in morphology, but they are separated by the branching of the ovary and testes as well as by the character of eggs. It is most likely that human paragonimiasis occurring in Cajamarca area is caused by the new species. The metacercaria belonging probably to P. peruvianus was found in a fresh-water crab, Pseudothelphusa chilensis collected in El Guayo, which is not infrequently eaten uncooked by inhabitants in that area. Ultimately, P. peruvianus seems to be very important in the medical field.