The present investigation deals with certain helminth parasites which infect the freshwater fishes in the Nile River and its common tributaries at Dakahlyia Governorate near El-Mansoura city, Egypt.The examined fishes were identified as Bagrvs hajad ; B.docmac; Synodontis schail: S. sen-aim; Mormyrus caschive; Barbus bynni; Lates mloticus and Labeo niloticm. These fishes were investigated monthly after weighing and measuring them and most of their internal organs were examined for helminth parasites.The following trematodes were recorded: Acamthodtomvm absconditum; Haplorchoides cahirinns; Phyllodistomum aegyptiacus; metacercariae of Diplostomum sp ; of Neodiplostomum sp and of Posthodiplostomwn sp. Moreover, two nematode species were reported, namely: Spinitectus moraveci and Capillaria yamagutii. Meanwhile, no cestode parasites were recorded in this study.Out of 400 collected fishes, 349 were found to harbour one or more types of parasites. The general infection rate was 87.25%. The infestation rate was highest in Bagrus baiad (97.7%) followed by Bagrus docmac (93.33%), while the lowest rate was recorded in Barbus bynni {69.1%).It was noticed that single infection was recorded for trematodes and nematodes in hostfishes. Double infection was not detected in Barbus bynni and was very rare in other fishes except B. hajad and B. docmac.The relation between fish host parameters (body length, weight and sex) and each of the prevalence and intensity of infection were studied in the present investigation. A significant correlation was found between the host length and infection prevalence, between the host weight and prevalence and between the host sex and intensity of infection, while insignificant relation was recorded between the host length or weight and intensity; and between host sex and prevalence of infection,