On the new investigation of some Trematode fauna of Arabian Gulf fishes, Monascus sp. a digenea parasite of pampus argenteus and Helicometrina nimia of greasy grouper, Epinephelus tauvina are register. Fish specimens were collected during the year 2016. A description of the studied specimens, besides comments concerning its taxonomic status, the morphological characters and measurements of the present material of Monascus sp. The Monascus sp. parasite are described on the present study compared with some measurements of Nine nominal species have been reported in the genus Monascus up to 1993 and showing that similarity with M. filiformis and differ in the size of parasite. The results indicated that the parasites are considered as having new hosts viz, p. argenteus and as new records in the Iraqi marine fishes. In the present study, a new host and a new host locality are presented for the two species. The taxonomic status of members of Helicometrina has been questionable, the validity of diagnostic features, especially in regard to the number of testes. In the present study, specimens presented a permanent and steady number of testes (n=9) and therefore its use as a diagnostic character and is very similar with Linton (1910). Epinephelus tauvina is considered a new host for Helicometrina nimia, and Northwest Arabian Gulf a new locality for the species.