To the best of the authors' knowledge, this is the first report on the electrochemical polymerization of 3,4-ethylenedioxythiophene on gold (Au) disk microelectrode arrays using sinusoidal voltages. The use of electrochemical impedance spectroscopy (EIS) for the in situ deposition of poly(3,4-ethylenedioxythiophene) (PEDOT) coating onto Au microelectrode arrays allowed the estimation of electrochemical parameters, such as charge transfer resistance and exchange current. The PEDOT coatings deposited on different arrays by sinusoidal voltages and potentiostatic methods were compared. The electrochemical characterization of both naked and PEDOT-modified microelectrode arrays by EIS and cyclic voltammetry (CV) revealed different diffusion regimes occurring at the microelectrodes surfaces. The electron transfer kinetics between the PEDOT coatings and redox probe in solution were also investigated. Results demonstrated the suitability of the new preparation procedure for electrogenerating PEDOT coatings. This novel procedure led to insights to the electrochemical properties and diffusion regimes occurring at both naked and modified microelectrode arrays. (C) 2012 Elsevier B.V. All rights reserved.