An Electrochemical chlorination of butadiene was investigated at 25 °C by using an H-type cell with a CoCl2–MeCN anolyte and an NH4Cl–H2O catholyte separated by an anion-exchange membrane. The electrolysis gave 3,4-dichloro-1-butene and trans-1,4-dichloro-2-butene in high current efficiencies.