Electrochemical and surface analysis techniques were used to study the mechanisms of CO2 corrosion of mild steel over the temperature range of 80-200oC. Experiments were carried out in a 4-liter autoclave equipped to perform in situ electrochemical measurements with both linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS). The electrolyte was 1 wt.% NaCl saturated with CO2 set to correspond to 0.03 M of