Emperor fishes, Lethrinus nebulosus are commercially important fishes in Saudi market. Despite of importance of these fishes, there is not a comprehensive report about parasitic fauna of these fishes. The aim of this research article is to determine the parasitic helminthes infecting these fishes in Saudi Arabia. For this purpose, 28 emperor fishes have been bought and examined by routine parasitological methods to find that 28.6% emperor fishes revealed intestinal trematode infections. Two trematodes were recognized in the fishes, Neolepidapedon (Neolepidapedon) macrum Overstreet, 1969 was found in 7 fishes (25%) and Opisthomonorcheides decapteri Parukhin, 1966was found infecting one fish only. Scanning electron microscope had shown absence of spines and revealed scale-like structure. Saudi Arabia is considered a new locality of those two trematodes and Emperor fishes as new hosts.