Recently, many individuals of greater one-horned rhino (GOHR) were died with unknown reason in Chitwan National Park (CNP), Nepal. This has arisen chaos and confusion in the rhino conservation program of the country. This study was designed to determine the prevalence of gastrointestinal parasites among GOHR in the CNP. A total of 100 dung samples were collected opportunistically by the random sampling method. Dung samples were preserved in 2.5% potassium dichromate solution and analysed in the laboratory by the direct smear and concentration method (floatation and sedimentation). Eggs and larvae of gastrointestinal parasite were found in 91% examined samples. Altogether 13 different genera of parasites were identified with one protozoan i.e. Eimeria sp. (9%), nine nematodes i.e. Strongyloides sp. (65%), Ascaris sp. (16%), Haemonchus sp. (15%), Dromeostrongylus sp. (9%), Oxyuris sp. (8%), Bunostomum sp. (8%), Chabertia sp. (5%), Trichostrongylus sp. (4%) and Nematodirus sp. (2%), one cestode i.e. Anoplocephala sp. (16%) and two trematodes i.e. Paramphistomum sp. (31%) and Fasciola sp. (14%). Nematode parasites were found to be most prevalent (87% of samples) followed by trematodes (45%), cestodes (16%) and protozoans (9%). The study indicates a high prevalence of gastrointestinal parasites in the GOHR of CNP and identifies that there is need of strategic control measures to protect this endangered species from parasitic infection.