The electropolishing of a boron-doped diamond (BDD) film deposited by chemical vapor deposition has been studied in acetic acid-H2SO4 media. The electropolished surface has been characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. The results have shown that in 1 M H2SO4 no polishing of the surface occurred even after prolonged time; on the contrary, in electrolyte containing 3 M acetic acid in 1 M H2SO4 the morphology changed rapidly. The surface became smoother and the roughness decreased as the typical results of a polishing process. All the non-diamond impurities were also removed by the electropolishing treatment in acetic acid media. (C) 2003 The Electrochemical Society.