A survey on endo-parasitic infections on Barboid fishes of South- West of Iran (Khouzestan province) was carried out from spring 2007 to atumn 2009. Altogether 296 specimens from five different fish species were examined, they are Barbus grypus Heckel, 1843; Barbus sharpeyi Günther, 1874; Barbus esocinus Heckel, 1843; Barbus barbulus Heckel, 1849 and Barbus pectoralis Heckel 1843. The fishes were collected from five stations of Karoun River (Ahvaz-Goulestan, Molasani, Dez Dam), Karkheh River (Hamidyeh Dam) and Shadgan Lagoon. The fishes transported alive to the laboratory where they measured and weighted. Then they were killed by cutting the spinal cord. According to the results of this study eight different species of endo-parasites were revealed, from which five of them identified to the species level and three to the genus level. The metazoans are as follows: Two digeneans: Diplostomum spathaceum Rudolphi, 1819; Asymphilodora sp. Looss, 1899; Five nematods: Rhabdochona denudate Dujardin, 1845; Philometra karuensis Pazooki & Molnar, 1998, Philometra sp., Pseudocapilaria tomentosa Dujardin, 1843 Contracaecum larvae sp. Railliet & Henry, 1912 and only one Acanthocephalus: Neoechinorhynchus tylosori. According the results of this study one new host; Barbus pectoralis for Diplostomum spathaceum form Iranian freshwater fishes was introduced and Neoechinorhynchus tylosori for the first time was recorded from Barbus barbulus from Iran.