Objective: The aimof the present studywas to evaluate the indicative role of hydrogen peroxide (H2O2) in oxidative stress. Patients andmethods: 200 type 2 diabeteswere included and 200 controls. Hydrogen peroxide (H2O2), glycated hemoglobin (HbA1c), free fatty acids (FFA) and homocysteine were determined by commercial kits. Quantitative insulin sensitivity check index (QUIKI) was calculated. Results: H2O2 concentrationwas increased fourfold in type 2 diabetes compared to controls. 6 correlationswere found: betweenH2O2 and HbA1c (r = 0.85, p<10-3), betweenH2O2 and FFA(r = 0.9, p<10-3), between H2O2 and homocysteine (r = 0, 5, p<10-3), between H2O2 and IS (r = -0.92, p<10-3), between the presence of H2O2 and arterial hypertension (t = -4, p<10-3) and between arterial hypertension and homocysteine (t = -7, p<10-3). Conclusion: The overproduction of H2O2 generated by hyperglycemia, increased dose of FFA and hyperhomocysteinemia, amplify the insulin resistance and induce arterial hypertension.