This study was carried out on 70 Rachycentron canadum (Cobia) collected from Red Sea to investigate the presence of acanthocephalans parasites and their deteriorated effect on fish. The clinical picture of naturally infested cobia showed no pathognomonic signs except slight emaciation or abdominal distension in some fishes. Postmortem lesions were manifested as congested internal organs, hemorrhages in the viscera and paleness in the liver with presence of many acanthocephalans parasites in body cavity either adhering or encysted in the viscera of fish. The total prevalence rate of infested fishes with acanthocephalans was 100% and intensity rate was 3-30/fish. The isolated Acanthocephalans were identified as Serrasentis sagittifer. The morphological characters of isolated parasite were described. The obtained results of the histopathological alteration of the affected fishes showed loss and severe sloughing of intestinal villi and lining epithelia with decrease in mucosal layer thickness and complete detachment of lining mucosa. Some muscle bundles revealed hyaline degeneration. Moreover, the damages associated with the tissue affecting its functional efficiency and the overall health status of the fish.The public health importance was discussed according to published records.