This work presents a method to study corrosion reactions in real time by the analysis of a temporal series of micrographs using in situ optical microscopy coupled to electrochemical techniques. The approach was applied to study the pitting corrosion of AISI 1040 steel during chronoamperometric measurements, in carbonate and chloride solutions. Using this coupled approach, it was possible to measure different pit parameters as well as to estimate the mean pit depth. The number of pits and the total pit area presented different behaviors as the chloride concentration increased and active and passive pits were detected. (c) 2014 Elsevier Ltd. All rights reserved.