The genus Serrasentis is one of important acanthocephalan parasites, parasitizing fish, birds and other vertebrates. Twenty two out of 500 fish specimens (4.4%) were found to be naturally infected with adult and cyst of worms of Serrasentis sp. which were collected from the stomach and intestine of Synaptura orientalis; Johnius belangrii, Otolithus ruber and Upeneus sulphureus fish species', from locations of Khor Abdullah, Arabian Gulf, Iraqi marine waters (29°58,33, N48°28, 20E) during the year 2017.The light and SEM study revealed that the adult worm have elongated and cylindrical body, anterior extremity with hooks forming combs arranged on the ventral and lateral region, longitudinally curved U-shaped, the Proboscis are claviform in shape and the measurement are equal to 0.54 long to 0.28 width, with 22-26 rows of 14-18 hooks, hooks thicker in ventral than dorsal parts, decreasing in size from the apex to the base. Proboscis receptacle with a thick double wall. The cross examination of Upeneus sulphureus fish intestines and food items containing revealed that are consists of different species of amphipods, and crustaceans, The present finding species are compared morphologically with some of the previously recorded species isolated from different host species, which revealed that the present species should be classified as Serrasentis sp. with a new host record in Upeneus sulphureus fishes.