Process for the manufacture of 1,2-dichloroethane starting with a hydrocarbon source according to which: a) the hydrocarbon source is subjected to a first cracking step, namely a pyrolysis step performed in a cracking oven, thus producing a mixture of cracking products; b) the said mixture of cracking products is subjected to a succession of treatment steps ending with a drying step which makes it possible to obtain a mixture of products containing ethylene and other constituents; c) the said mixture of products containing ethylene derived from step b) is separated into at least one fraction containing ethylene and into a heavy fraction; d) the fraction(s) containing the ethylene is (are) conveyed to a chlorination reactor and/or to an oxychlorination reactor, in which reactors most of the ethylene present is converted to 1,2-dichloroethane; e) the 1,2-dichloroethane obtained is separated from the streams of products derived from the chlorination and oxychlorination reactors; the process being characterized in that a step for hydrogenating the acetylene is carried out upstream of the drying step ending the succession of treatment steps constituting step b) and/or on at least one of the fractions containing ethylene after separation during step c).