Magnesium ion (Mg²⁺) plays an essential role in various cellular functions. Mg²⁺ deficiency or abnormal Mg²⁺ metabolism is related to various cardiovascular diseases, such as ischemic heart disease and arrhythmias. Recently, various candidate genes of Mg²⁺ transporters are reported, but their functional roles are still unknown. We first treated mice with three kinds of magnesium diets (low-magnesium diet, normal-magnesium diet, or high-magnesium diet) for 4 weeks, and found that the tissue expression levels of several Mg²⁺ transporters were dependent on magnesium intake. We also found that phenylephrine-induced contraction was attenuated in isolated aorta from low-magnesium-fed mice. Furthermore, to investigate the functional roles of these Mg²⁺ transporters, we generated several genetically altered mice targeting their Mg²⁺ transporters. Interestingly, phenylephrine-induced contraction was reduced in isolated aorta from these genetically altered mice. On the other hand, when these genetically altered mice were fed with a high-magnesium diet, the phenylephrine-induced contraction was recovered to normal level. These results suggest that these Mg²⁺ transporters may play important roles in the maintenance of Mg²⁺ homeostasis and vascular functions.