The electrochemical reductions of three ethoxysulfonium ions, diphenylethoxysulfonium (1), methylphenylethoxysulfonium (2), and dibenzylethoxysulfonium (3) hexafluorophosphate, have been studied in acetonitrile solutions in the presence of both tetraethylammonium (TEAP) and sodium perchlorate electrolytes. These salts are reduced to a mixture of the corresponding sulfide and sulfoxide in an overall one-electron process. For (1) and (2) an equimolar mixture of sulfide and sulfoxide is obtained in NaClO 4 solutions, while the yield of sulfide is larger than the sulfoxide yield in TEAP electrolytes. Electrolytic spin trapping experiments with α-phenyl-tert-butylnitrone have implicated radical intermediates in these electrolyses. Electrode reactions consistent with the e.s.r. spectra of the spin adducts and electrolysis products are proposed.