This study was conducted to ivnestigate the associations ofGH-AluI, STAT5A-AvaIandMYF5-TaqIgene polymorphisms with milk somatic cell count (SCC), electrical conductivity (EC) and pH levels in Holstein dairy cows. For this purpose, 167 blood and 1670 milk samples of 167 Holstein cows in their 2nd lactation were used. There were significant relationships betweenGH-AluI genotypes and milk EC (p < 0.001) and betweenSTAT5A-AvaI genotypes and milk EC (p = 0.007), but there were not any significant relationships betweenMYF5gene polymorphism and the investigated traits (p > 0.05). The greatest EC values were observed inGH-AluI-LV andSTAT5A-AvaI-TT-genotyped individuals. Just because of association of EC with mastitis, it was concluded that presentGH-AluI andSTAT5A-AvaI polymorphisms could be used in further studies to be conducted to improve mastitis resistance and milk quality traits of Holstein dairy cows.