Abstract: Calpastatin（CAST） gene expression diversity among chicken various breeds and tissues was investigated by using semiquantitative RT-PCR.To collect the tissue samples ,20chickens of 5 breeds were slaughtered.The results indicated that CAST gene were expressed in chicken various kinds tissue. The expression in chest muscle was more significant than in other organiz (P < 0.05).moreover,it was identified that CAST gene expression in Avian Broilers was higher than in Vans Nera egg chicken and adequate quality broilers muscles(P <0.05).