This study investigates the effects of a polymorphic site (MSTN_DraI) in the myostatin gene on the growth performance of beef cattle. Using 240 F2 crossbred cattle of 8 groups, the research assessed growth traits across different genotypes (AA, AB, BB) of the MSTN gene. The results showed that at the day of 360, animals with the AB genotype had an average body weight of 286.3kg, those with the AA genotype had an average body weight of 282.3kg, and those with the BB genotype had an average body weight of 271.1kg. Average daily gains from birth to 360 days were 712, 702 and 660 g/day for AB, AA, and BB genotypes. The homozygous (AA) and heterozygous (AB) genotypes showed the best outcomes in cattle weight at 360 days and average weight gain. The high frequency of allele A (0.81) suggests that phenotypic selection has influenced the genotype distribution within the herd. Cattle with superior genotypes exhibit better growth performance; therefore, breeding selection based on the MSTN_DraI marker is expected to lead to further improvements in this trait.