The inhibition efficiency of caffeine in controlling corrosion of carbon steel immersed in 60 ppm of Cl- ion environment has been evaluated, in the absence and presence of Mn2+ ions, by weight loss method. Influence of sodium dodecyl sulphate, pH and immersion period on the inhibition efficiency of the caffeine-Mn2+ ion system has also been investigated. The protective film formed on the metal surface has been analysed by FTIR spectra. The protective film consists of Fe2+ - caffeine complex and Mn(OH)(2).