In this study, the effect of vitamin E plus selenium (Se) application on malondialdehyde (MDA), glutathione (GSH), vitamin E, C, A and -carotene were aimed to investigate in exercised horses. For this purpose, 50 healthy Anatolian type local horse breed aged between 3-5 from Altındere Study Farm were used. The animals were divided into two equal groups. While 1st group received nothing, horses in second group were received vitamin E+Se intramuscularly. Then animals in both groups were exercised for 1500 meters. Blood samples were taken handily from all animals before and after exercise. This samples were analyzed for MDA, GSH, vitamin E, C, A and β-caroten spectrophotometrically.MDA and GSH concentration in 1st group were found to increase significantly (p<0.001) after exercise. On the other hand, serum vitamin E, C, A and β-carotene levels did not changed significantly. In the second group, serum vitamin E levels increased significantly (p<0.001) after vitamin E+selenium application. Furthermore, MDA (p<0.05) and GSH (p<0.001) levels increased significantly after exercise in the second group. Vitamin E levels decreased significantly (p<0.01) after exercise. However, vitamin A and C levels did not change significantly. In addition, in the second group, β-carotene levels were also changed significantly (p<0.05) when the values obtained before vitamin E application compared with the values obtained after vitamin E application. When comparison made between groups, while MDA and vitamin E values were statistically important (p<0.05), GSH, vitamin C, A and β-carotene values were not important statisticallyAs a result, acute exercise can increase free-radical production which, the results shows that increase in both MDA and GSH can be shown as the indicator of it. Furthermore, decrease in MDA level in vitamin E applied group the indicator of the rise in antioxidant defense and protective effect of vitamin E.