Reductive desorption of selcassembled monolayers of thiols is reviewed. Cyclic voltammetry for the reductive desorption of adsorbed thiols is sensitive to not only the chain length and the kind of the terminal functional group but also the state of adsorbed thiols. The importance of the elucidation ofthe relationship between microscopic structure studied by scanning probe microscopy and cyclic voltammograms for the reductive desorption is emphasized. The reductive desorption is also useful to form phase-separated binary monolayers into nanometer-scale by the electrochemical selective replacement of adsorbed thiols.