The experimental mice were induced Alloxan Monohydrate (AM) at 150 mg/kg of the body weight. Then, they were orally administered methanol extract of the young leaves of mango (Mangifera indica). The antidiabetic effect of extract leaves of mango was compared with standard antidiabetic drug Glucophage. The results proved that the extract of Mangifera indica leaf controls blood glucose concentration in diabetic mice. The young leaves extract (Mangifera indica) at concentrations 200 and 400 mg/kg also possessed a significant hypoglycemic effect and did not affect body weight of normal rats after 20 days of the experiment. The experimental results showed that young leaves extract at levels 200 and 400 mg/kg produced a reduction of blood glucose level in normoglycemic and glucose-induced hyperglycemic effect on AM induced diabetic mice. In addition, the total polyphenols and flavonoids contents of young leaves extract were 335.06 1.84 mg Gallic acid or Quercetin equivalents/g and 432.86 10.01 mg equivalents/g, respectively.