In this study, we aimed to investigate correlation between free radicals and antioxidants in healthy and diabetic rats. For this purpose, we assessed Homocystein, Leptin, Vitamin A, E, C levels and some lipid parameters levels with MDA in healthy and diabetes-induced rats. In this context, HCY, leptin, Vit A, E, C and some lipid parameters with MDA were evaluated in 10 weeks old 20 healthy and 20 rats with experimentally-induced diabetes. Plasma MDA levels were found to be significantly increase in diabetic group when compared to control group (p<0.05), but HCY, leptin and Vit C levels found to be significantly low in diabetic group when compared to control group (p<0.05). No difference was observed between the control group and diabetic group in plasma Vit A and Vit E levels. HDL was found to be significantly low in diabetes group when compared to control group (p<0.05), but cholesterol, triglyceride and LDL found to be significantly high in diabetic group when compared to control group (p<0.05). In this study, low homocysteine levels have no risk for cardiovascular disease but it must be noted that increased weight after low leptin level, as well as high serum cholesterol levels and increased MDA levels have induced some metabolic disease e.g. heart disease and hypertension.