The corrosion behavior of mild steel in the presence of acetic acid (CH₃COOH) and carbon dioxide (CO₂) has been investigated using electrochemical techniques and weight-loss measurements. Electrochemical measurements have shown that the presence of acetic acid affects predominantly the cathodic reaction. The acetic acid effect is much more pronounced at elevated temperatures when catastrophic corrosion rates may be encountered at high concentrations. The undissociated form of acetic acid, present at lower pH, is responsible for the increases seen in the corrosion rate.