The viability of using An surfaces made from An evaporated on glass plates with a Cr underlayer was studied for the electropolymerization of 3-methylthiophene. Poly-3-methylthiophene films were prepared using cyclic voltammetry in an acetonitrile medium by varying the potential range, monomer concentration, etching treatment of Au, and the electrolyte salt. After a relatively high potential was applied, which is necessary to oxidize the monomer, dissolution of the Au overlayer occurred, particularly when tetrabutylammonium tetrafluoroborate was used as the electrolyte salt. Strong evidence points to contaminants such as chloride as the Au dissolution initiator. The pretreatment of the electrode surface also affected the voltammetric response of Au, because dissolution is accelerated after using wet chemical etches. X-ray photoelectron spectrometry was used to verify the exposure of the Cr underlayer by dissolution of Au.