Most of the electrochemistry of chalcopyrite reported in the literature has been done using either massive samples of the mineral or carbon paste electrodes. Despite its importance, reports of the electrochemical behavior of this mineral carried on individual microparticles are scarce. In this work the microelectrochemistry of chalcopyrite is studied in sulfuric acid solutions, focusing the study on its behavior at transpassive potentials. It is shown that microparticles with sizes typically found in chalcopyrite concentrates (20 to 100 mu m) can be leached to completion in less than 4 minutes at room conditions under the influence of 1.2 V (SCE). According to EDX analysis, atomic absorption spectroscopy and ICP, around 88% of the sulfur in the mineral is transformed into a compact layer of amorphous plastic sulfur, while the rest is transformed to sulphate. The plastic sulfur gradually equilibrates to more stable Sg-rings orthorhombic phase. This nearly instantaneous dissolution of chalcopyrite opens the window to the development of new technologies. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.007201jes]