The inhibition mechanism of the Cashew Nut Shell Liquid (CNSL) on SAE 1008 carbon steel corrosion in CO 2 saturated 3% NaCl solutions has been studied by weight loss, UV/VIS and electrochemical techniques. The phenoxide, R-Ar-O-ions from the CNSL inhibitor were found to be responsible for the reduction of the corrosion rate of the carbon steel. Also, it was observed that the surface charge of the carbon steel electrodes was positive with respect to the solutions containing CNSL inhibitor. It is likely that the electrostatic attraction between the mechanism of the CNSL inhibitor adsorption involved the positively charged metal surface and the phenoxide ions via their negative ends.