Fish like any other organisms, are susceptible to ecto & endo-parasites, which have a risky impact in aquaculture specially those because skin infection with secondary bacterial infection. This study estimated the parasitic infections in freshwater Catfish (Clarias gariepinus) in Assiut Governorate, and evaluated environmental factors affecting them.A total of 100 samples of different sexes and sizes were randomly collected weekly over one year from different localities in Assiut City. The fish were examined parasitological for ecto-parasites and dissected for endo-parasites as well as histopathological examination of muscles.The results showed an overall parasitic rate of 82%. Ecto-parasites were Gyrodactylus, Dactylogrus, Henneguya and Icthyophthirius multifiliis (2%, 8%, 2% & 5%) respectively, while endoparasites were trematode (Orientocreadium batrachoides 26%), cestode (Polyochobothrium clarias and Monobothrioides 6% & 21% respectively), nematode (Paracamallanus spp. 12%), encysted metacercaria (66%) and protozoa (Entamoeba spp. 15%). The variation between the parasitic number length, weight, and sex seasonally were statistically analyzed.