The determination of adsorbate surface concentration and its dependence on fundamental electrochemical variables is of paramount importance in studies of electrode processes, electrocatalysis and corrosion. In this paper we review the current status of a radiotracer method that permits measurements of adsorbate surface concentrations on surfaces of smooth solid electrodes of a convenient size and thickness. Several examples are presented of the most representative measurements carried out with polycrystalline platinum, gold and copper electrodes, and with platinum single-crystal electrodes. We discuss the interdependences between surface concentrations and voltammetric currents, and provide detailed characteristics of the molecular adsorption of pyridine and the anionic adsorption of sulfate on a clean and an admetal-covered electrode surfaces. We also report on a new all-glass cell design that facilitates cleaning and a convenient observation of the cell interior during measurements. We believe that the performance of this method, and the cell design concepts, have been verified to the point that the technique can now be recommended for broader use, especially in applied electrochemistry where coverage measurements are essential and the need for a spectroscopic focus is less apparent. However, since possibilities for joint radioanalytical and spectroscopic measurements are numerous, the resulting complementary interpretation may contribute equally effectively to both fundamental and applied electrochemical surface science.