High deuteration yields are difficult to attain with conventional chemical synthesis methods. In this work, we demonstrate that deuterated chemicals can be produced using electrochemical CO2 reduction in the presence of D2O. The absence of H2O enables deuteration yields over 99% for products such as ethanol-d(6) and formate-d. With a D2O solvent, the competing D-2 evolution reaction is completely suppressed at low current densities while being kept <10% at a higher 300 mA/cm(2).