The electrochemical synthesis of cyanoacetic acid was performed by cathodic reduction of tetraalkylammonium salts (R4NX) in acetonitrile in undivided cells equipped with sacrificial anodes with concomitant or subsequent addition of carbon dioxide. These syntheses avoid the use of dangerous reagents, yield cyanoacetic acid in moderate faradic yields and confirm that the cathodic reduction of tetraalkylammonium salts in the presence of acetonitrile leads to the formation of the anion CNCH2-. (c) 2007 Elsevier B.V. All rights reserved.