This work deals with the effect of nitrite ions on the breakdown of passive films formed on steel in simulating pore concrete solutions with a high content in carbonate ions. The solutions contain 0.015 mol l(-1) Na2CO3 and 0.3 mol l(-1) NaHCO3 and may incorporate 0.05 or 0.1 mol l(-1) NaCl. The inhibition efficiency is evaluated recording cyclic voltammograms, polarization curves, polarization resistance, impedance and Raman spectra. Weight-loss measurements were also performed. High CO3-2 concentrations favor the development of a passive film that becomes more compact when nitrite ions are added. As the [NO2-]/[Cl-] increases, the films become more resistant to pitting attack. A linear relationship was established between E-pit and log ([NO2-]*([HCO3-] + [CO3 (=)])/[Cl-]). It is shown that the [NO2-]/[Cl-] ratio cannot be taken as an appropriate parameter to evaluate the inhibitor efficiency for different pH values and different carbonate and chloride ions concentrations. Instead, the results showed that exceeding [NO2-] = 0.2 mol l(-1) can be taken as a better criterion for the level needed for adequate protection in the various electrolytes studied. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.006206jes] All rights reserved.