Four sulfated fatty acid diethanolamine complexes (DC) were synthesized based on four different types of vegetables oils and tested as corrosion inhibitors of mild steel in CO2-saturated 1% NaCl solution at 50 °C. Results ob-tained show that the surfactants studied are efficient corrosion inhibitors for mild steel even at low concentrations. It is found that the inhibition efficiency increases with the concentration, and the good inhibition efficiencies are reached near their critical micelle concentrations (99.95% at 100 ppm). The adsorption of inhibitor on the steel surface obeys the Lang-muir adsorption isotherm equation and was chemisorption. Energy dispersive X-ray fluorescence microscopy (EDRF) ob-servations of the electrode surface confirmed the existence of such an adsorbed film.