As part of an ongoing research project concerning the diversity and distribution of parasites of Caviidae in South America, 143 wild guinea pigs (Cavia aperea) were collected from 3 localities in the Andean Highlands of Peru. Samples were collected between November 1996 and May 1999 and included representatives of arthropods, nematodes, and trematodes. Seven species of arthropods: Leptopsylla segnis (27.3%), Tiamastus cavicola (6.9%), Gliricola porcelli (55.2%), Hoplopleura alata (6.9%), Polyplax spinulosa (12.6%), Myobia musculi (1.4%), and Eutrombicula bryanti (49.6%); 4 species of nematodes: Capillaria hepatica (6.9%), Graphidioides mazzai (18.8%), Trichuris gracilis (3.5%), and Paraspirudera uncinata (37%); and a single trematode, Fasciola hepatica (4.2%), were identified.