Abstract: A method for preparing 1,2-dichloroethane which comprises electrolysis of a 12-36% aqueous solution of hydrochloric acid having temperature of from 45.degree. to 70.degree. C. simultaneously with supplying ethylene into the anodic space. Prior to the electrolysis, into the aqueous solution of hydrochloric acid, an additive is introduced which comprises a metal of the group of iron, or a compound of a metal of said group, or an alloy containing at least one metal of the group of iron, or any mixtures of the above-mentioned substances; the additive is introduced in such an amount that the concentration of ion of the iron group metals in the aqueous solution of hydrochloric acid is equal to at least 0.006 g-ion per liter of said solution.1,2-Dichloroethane may be used as a solvent. Furthermore, 1,2-dichloroethane is useful in the production of vinyl chloride which is an important starting monomer for the manufacture of polymers.