Gold nanowell electrode arrays, with a well-depth of approximately 50 nm, have been prepared. The electrodes were prepared by the electrodeposition of gold throughout the pores of a porous alumina membrane. Both electrochemical gold stripping and ion bombardment were employed to remove gold to create the wells, with the best results obtained from a combination of these techniques. The nanoelectrode arrays were characterized by scanning electron microscopy, atomic force microscopy, scanning tunneling microscopy, and by electrochemical methods. (C) 2003 The Electrochemical Society.