The mara (Dolichotis patagonum) is a species classified as “Near Threatened” by the International Union for Conservation of Nature. In the wild, it inhabits only Argentina, but it is also kept in zoos around the world. In order to investigate the endoparasites of the maras kept in the Attica Zoological Park, Greece, four fecal examinations were performed in a period of 4 yr (2008–2011) by standard parasitologic methods. Cysts of the protozoan parasite Giardia spp. and eggs of the nematode Trichuris spp. were found in all four examinations. The possible routes of infection of the maras and the importance of these parasites to other animals and to humans are discussed.