The development of a pickling process, more effective and appropriate for the new steel grades, requires a deep and thorough knowledge of its interaction with the steel surface. The Surface ICP-OES technique developed for some years at ARCELOR RESEARCH SA, has permitted to obtain the electrochemical and chemical characterization of pickling, in real time, up to now on laboratory samples. The principle and the developments of this technique and its transfer to pickling are presented. The results obtained in some cases highlight the potential and the interest of this approach for an improved control of the pickling process.