A total number of 150 different marine fish species represented as 50Argyrosomus regius(L ute fish) from Mediterranean Sea at Damitta Province,Egypt,50 Pagrus pagrus (Morgan fish) from Mediterranean Sea at Matrouh Province, Egypt and 50Xiphias gladius(Abo saif fish) from the red sea at Hurghada city ( south of Sinai province) , Egypt . The incidence of parasitic isopods among 150 marine fish was 4%. Specimens were subjected to parasitological examinations for detection of isopod infestations. The detected parasites were Anilocra leptosome and Cymothoa indica from Argyrosomus regius and Pagrus pagrus respectively while no infestation recorded in Xiphias gladius. The infestation rate with Anilocra leptosome and Cymothoa indica was4 and 8% respectively.The parasites observed in the gill chamber of the host.. The morphological characteristics of these parasites were described in details using light and scanning electron microscopy.