Equus ferus przewalskii, currently assumed as subspecies of E. ferus, is considered as endangered by the International Union for Conservation of Nature (IUCN). The ex situ conservation has been crucial for the continued preservation of this subspecies, once considered extinct in the wild. The Pentezug Wildhorse Reserve, located in the Hortobágy National Park, in Hungary, has one of the biggest ex situ populations of Przewalski’s horses and it’s aimed to preserve its typical landscape and to study wild horses in a semi-wild habitat, making part of this subspecies reintroduction plan. Currently, this population comprises almost 280 Przewalski's horses, sharing the area with a population of domestic cattle (Bos primigenius taurus), carefully bred to reconstructed aurochs (Bos primigenius). In this study, 79 faecal samples were collected and the coprological methods (McMaster, Willis floatation, natural sedimentation, Baermann and coproculture) and corresponding microscopic identification were performed in all the samples. Results show an average level of 1286.7 Eggs per Gram (EPG), which is considered a high level of parasitism. All the 79 samples analysed were positive for strongylid-type eggs (100% prevalence)(79/79), with a dominance of the cyasthostominae, when compared to strongylinae and tricostrongylidae. Moreover, a total of 15 different morphological L3 types and/or species identified of the order Strongylida. Additionally, 27.8%(22/79) were positive to Parascaris sp. and 2.5%(2/79) contained Oxyuris equi in their expelled faeces. By the sedimentation method, we could only evidence a Trematoda egg (1/79). In the subfamily Cyathostominae, L3 of cyathostomins type A showed 100% prevalence. In Strongilinae, Strongylus vulgaris is the most prevalent (40.5%), followed by Triodontophorus serratus (12.7%). These results are consistent with the other studies performed in the same subspecies and represent the first survey of gastrointestinal parasites performed with this level of detail in this population of Przewalski’s horses. Statistically, this study revealed that animals infected by Parascaris spp. tend to be positive in association with cyathostomins type C. In the same way, animals infected by T. serratus tend to be positive for Poteriostomum spp., possibly due to the propensity of juveniles for these two parasites revealed in this study. Furthermore, males have more S. vulgaris infections than females and animals infected by S. vulgaris tend to have lower levels of EPG. These results reveal the importance of parasite monitoring in wild ex situ populations, especially those that can be part of a reintroduction program, to better-knowing their pathogenic potential, possible parasite associations, predisposition factors and consequences for the subspecies conservation.