In this study, the polymorphism of Transferrin (Tf) systems were investigated in 1315 Arabian horses blood samples to determine the parentage control. Using potyacrylamide gel electrophoresis (PAGE), fifteen phe-notypes controlled by five codominant allele were determined in Tf systems. Allel frequencies were as follow; TfF₂=0.431, TfH₂=0.211, TfD=0,183, Tf0=0.165 and TfF1 =0.010. Homozygotes F₂F₂ phenotype has maximum frequency (% 18.71) and F1F( and F,0 have minimum frequency (% 0.15) these are three of the fifteen phenotypes determined: DD, DF₁, DF₂, DH₂, DO, F₁F₁, F₁F₂, F₁ H₂,F₁O, F₂F₂, F₂H₂, F₂O, H₂H₂, H₂O and OO. The findings in this study suggest that Hardy-Weinberg balance was observed in this population (p> 0.01)