We surveyed gastrointestinal and ectoparasites in wild and domestic ungulates in the Selva Lacandona, Chiapas, Mexico, including Baird's tapir (Tapirus bairdii), collared peccary (Pecari tajacu), white-lipped peccary (Tayassu pecari), white-tailed deer (Odocoileus virginianus), red brocket deer (Mazama americana), horses (Equus caballus), cattle (Bos taurus), and pigs (Sus scrofa). We collected 97 fresh fecal samples from the domestic species and 46 from the wild species and examined digestive tracts of 21 wild specimens. We identified 18 species of nematodes and 7 species of protozoans in feces and 3 nematode species, 2 trematode species, and 1 cestode species during postmortem examination. Paramphistomid infections in peccaries and deer were both prevalent and intense, representing a potential risk to populations of these ungulates. Ectoparasites included 14 species of Ixodidae and a hippoboscid. Of the endoparasites, 10 are new host records and 15 are new geographic records for Mexico. Ectoparasites included 7 new host records and 14 new geographic records for Mexico. Morisita's similarity index revealed the greatest similarity between the 2 deer species and between the 2 peccary species, while the greatest similarity between wild and domestic species was between B. taurus and O. virginianus. We discuss possible routes of interspecific transmission as well as the potential of the ectoparasites identified as disease vectors.