Abstract: Objective To investigate the effect of vitam in E(VE)and magnesium supp lementation on insulin resistance and antioxidative capacity in diabetic rats.Methods Eighty-eight Wistar rats were randomly assigned to control group,VE group(E),middle,high-dose magnesium group(MM,HM),and VE plus middle-,high-dose magnesium group (EMM,EHM).Four weeks after different diettreatment,all rats were injected wtihs treptozotoc in to provoke diabetes millitus.After another 4 weeks of feeding,all rats were sacrificed.Insulin resistance index(IRI),glutathione perox idase(GSH-Px),supe roxide dismutase(SOD),and hemolytic degree of redblood cell were detected.Results Compared to the control group,IRI in E,EMM and EHM groups was decreased by 5.52,3.29,and 2.65,respectively(P<0.05).GSH-Px and SOD activity in EHM was significantly increased to 41.65±2.99 and 1.9149±8.03 U/mg prot(P<0.01).The erythrocyte hemolytic degree was decreased by 67.86%,7.143%,60.71%,89.29%,and 89.29%in E,MM,HM,EMM,and EHM,respectively(P<0.05).Conclusion Supplem entation of VE and magnesium is more effective than VE or magnesium alone to attenuate the insulin resistance by increasing the an tioxidative capacity and decreasing the lipid perox idation in diabeticrats.