Mullet fish provide a valuable role in aquaculture to meet the rising demands for fish production in Egypt. The accurate estimate of species limits is a key factor in improving mullet fish for the application in evolution, conservation and management of the genetic programs. Four species of mullet fish, “Mugil cephalus, Liza ramada, Liza aurata, and Liza saline" were investigated by RAPD analysis to assess the genetic structure. Mullet fish were collected from three locations in the Mediterranean Sea (Al Maadyeah – Al Manzala – Bardawil). RAPD assay was performed using 10 decamers random primers; all the ten primers were succeeded in producing distinct bands.The obtained results revealed that the number of reproducible bands analyzed for ten primers for Al Maadyeah fishes was 181 bands in all four species, but in Bardawil and Manzala were 224 and 229 respectively. In each interspecies Mullet variation, the polymorphic amplified bands were 78.12% from it (20.98% M. cephalus 5.35% L. aurata, and 16.07 % Liza ramadaunique bands) in Al Manzala, and 73.79% polymorphic from it (20.96% M. cephalus, 4.36% L. aurata and 12.2% L. ramada unique bands) in Bardawil and 66.85% polymorphic bands for Al Maadyeah from it (11.6% M. cephalus 8.2% L. aurata, 1.1% for L. ramada and L. salineunique Bands). Nei's genetic distance between (0.503 – 0.719) in Al Manzala, (0.263 – 0.514) in Al Maadyeah and (0.271 – 0.537) in Bardawil. The RAPD technique can be introduced as an easy tool in the population genetics of marine fishes, providing supplementary information in their genetic stock structure analysis.