Nine natural population of Nile Tilapia (Oreochromis niloticus L.,) were collected from different governorates in Egypt to calculate the genetic polymorphism with/within the different populations. Collected fish samples were subjected to DNA extraction using arbitrary short (10 nucleotides) primers randomly amplified polymorphie DNA -PCR. In a total of 726 amplification fragments; 430 were polymorphic and 296 were monomorphic with general genetic polymorphism percentage 59.23%. The recorded results indicated that there were high significant variations regarding the population from different location in Egypt. The genetic polymorphism in the different populations were (56.84%) in Marsa Matroh governorate: Siwa oasis (54.43%) and Al-Negelia (59.25%); (60.08%) in Alexandria governorate: Abis (59.34%), Alameryia (60.82%); (59.26%) in El-Beheria governorate: Nobariya (59.21%), Edko (58.02%), Rosetta (60.56%); Kafer Elshikh governorate: Desuq (59.64%) and 59.74% in Aswan governorate. The highest amplification fragments were recorded to OPN-10 (98), OPQ-14 (90) and OPM-5 (86) primers, in respect.