Recent work in this laboratory involving the fabrication of single crystal ultramicroelectrodes (SCUMES) of gold and platinum is summarized in this paper. The method for growing the gold and platinum single crystals of micron dimensions is discussed in detail and the technique for incorporating these crystals into ultramicroelectrodes is described. The electrochemical response of these ultramicroelectrodes is shown with cyclic voltammograms recorded in selected electrolytes. The atomic force microscopy (AFM) images of the platinum and gold crystals, which were used to make the ultramicroelectrodes, are also presented.