The inhibition effect of chromate (CrO42-) and molybdate (MoO42-) anions on the pitting corrosion of 16Mn carbon steel in 0.1 M NaCl containing bicarbonate solution was studied based on electrochemical noise analysis (ENA) and the potentiodynamic polarization method. The experimental results indicated that, once the pits occur on the surface of the carbon steel after 4-6 h of immersion, increasing the concentration of CrO42- and MoO42- ions accelerate the repassivation process, and attenuate the duration and the nucleation rate of metastable pits. Further analysis demonstrated that noise resistance R-n might not be suitable for the evaluation of the inhibition efficiency of CrO42- and MoO42- anions on pitting corrosion in the present system. However, the transient charge q(pit), which is an integral of all current transients during a certain period, can characterize the inhibition performance on pitting corrosion. A new definition of inhibition efficiency based on q(pit) is given.