Surface enhanced Raman spectroscopy was used to study species present on carbon steel in CO2 and N-2 saturated brines at 24 and 65 degrees C. in the presence of CO2, a surface carbonate species, characterized bg a peak at 1078 cm(-1), was observed on the cathodically polarized steel surface. In CO2-saturated solutions, iron oxide/hydroxide corrosion products formed at the cathodic potentials studied (-900 and -1100 mTi SCE), while such products were not detected on steel at these potentials in N-2-saturated brines.