ABSTRACT In this study, a sample of 144 persons lived in middle-Euphrates of Iraq population was analyzed using 5 Y-chromosome short tandem repeat (STR) polymorphisms. This population (n=144) was separated to two sub-population Hashemites (n=72) and Commoners (Non- Hashemites) sub-population (n=72), in the commoners sub-population the locus DYS19 was most polymorphic loci in number of alleles with the highest gene diversity, while in Hashemites sub-population, the locus DYS19 and DYS392 were most polymorphic loci in number of alleles and DYS391has the highest gene diversity. In study of Y STR Haplotypes, it found 62 haplotypes in all populations 52 were unique haplotypes, the Hashemites sub-population the number of haplotype was 27, the unique haplotypes were 19, and in the commoners sub-population the number of haplotype was 35, the unique haplotypes were 33 haplotypes and has a highest haplotype diversity and Discrimination Capacity.