This research was carried out to investigate the polymorphisms of Myostatin gene in Holstein Friesian and Brown Swiss cattle breeds. PCR-RFLP methods were used to investigate of MSTN gene. DraI restriction enzyme was used to detect of MSTN gene polymorphism. The result showed that there were two genotypes (AA and AB) of MSTN gene in two cattle breeds. The allele frequencies in Holstein Friesians were 0.97 and 0.03 while the allele frequencies in Brown Swiss were 0.88 and 0.12.Genotype frequencies in Holstein Friesian were 0.94 and 0.06 while the genotype frequencies in Brown Swiss were 0.77 and 0.23. The genotype distributions for these alleles in two cattle breeds were in agreement with Hardy-Weinberg equilibrium (P>0.05). If there is statistical significance in association analysis with this gene for meat characteristics and growth characteristics, this result can be used in the future to improvement of meat properties and growth characteristics in the cattle. Also, this study is also important in determining the status of these two breeds raised in Turkey and to shed light on those who will work on this issue.