The fabrication of scanning tunneling microscopy (STM) tips by de downward electrochemical polishing and ion milling has been investigated. The influence of parameters, such as voltage, immersion depth, cutoff time? and solution concentration, on the shape and sharpness of electropolished W tips are presented. Both electropolished and ion milled tips, which were characterized by transmission electron microscopy !TEM!, were tested on Au films deposited on [100] oriented Si. The effects of tip radius on STM images are discussed thoroughly, and the results are also compared to atomic force microscopy (AFM) and TEM images.