In situ acoustic emission (AE) was coupled with linear- sweep voltammetry from anodic to cathodic potentials to study 5N5-aluminum behavior in 4 M aqueous potassium hydroxide solution. We clearly highlight a correlation between the AE and electrochemical signals. Moreover, the different types (e. g., in terms of frequency) of AE signals detected, render possible the discrimination between the different electrochemical phenomena that can take place simultaneously on the electrode surface during the voltammetry, e. g., hydrogen evolution, oxide formation, etc. Such phenomenological discrimination was not achievable only using electrochemical measurements. (c) 2005 The Electrochemical Society.