Abstract: In a process for preparation of 1,2-dichloroethane by chlorination of ethylene-containing reaction vent gases from the oxychlorination of ethylene in the presence of a catalyst carrier impregnated with metal compounds wherein the waste from the oxychlorination stage are chlorinated, the improvement comprising preheating the ethylene-containing waste gases to at least 50.degree. C. and then chlorinating the ethylene at 100.degree. to 300.degree. C. at a pressure of 1 to 7 bar with a space velocity of 100 to 5000 h.sup.-1 related to standard conditions in the presence of at least one metal compound selected from the group consisting of chlorides and oxides of manganese, nickel and cobalt supported on a catalyst carrier with reduced formation of oxychlorinated by-products.