The gastrointestinal and external parasites and their level of infestation in the Arabian oryx (Oryx leucoryx) were studied at King Khalid Wildlife Research Center (KKWRC) in Thumamah, Riyadh Province, Saudi Arabia. Fecal samples were collected from 36 oryx while they were being handled for routine management at KKWRC; the samples were examined for gastrointestinal parasites. Protozoan oocysts detected in the present study were Eimeria saudiensis (prevalence 63.9%) and Cryptosporidium sp. Strongyle-type nematode eggs were present in 75% of the fecal samples. Nematodirus spathiger eggs (prevalence 55.6%) and Trichuris sp. eggs (prevalence 13.9%) were also recovered from the fecal samples. Additionally, 3 of 44 (6.8%) serum samples tested positive for toxoplasmosis antibodies. Carcasses of 6 oryx that died at the center were necropsied and all were infected with Camelstrongylus mentulatus, Trichostrongylus probolurus, and Nematodirus spathiger, whereas 3 animals were infected with Trichuris cervicaprae at relatively low intensities. Cysticerci of Taenia hydatigena were recovered from 3 of 6 necropsied oryx.