Abstract: A method for the hydrodechlorination of a reaction gas primarily composed of chlorinated hydrocarbons is carried out sequentially. A first step is advantageously carried out in a tubular reactor filled with catalyst and cooled externally, to maintain a temperature within a preferred range of 80.degree. to 230.degree. C. and a radial temperature difference of not more than 40.degree. C. Hydrogen is added to the tubular reactor with a hydrogen excess in a preferred range of 1.1 to 1.5 relative to the reaction gas, based on the stoichiometric consumption. The catalyst is present in a catalyst loading in a preferred range of 0.1 to 1.5 v/vh based on the volume of reaction gas. A fixed bed reactor is advantageously used for a second step, optimally connected in straight transit with the output of the reactor of the first step. The full-space reactor is maintained at a temperature within a preferred range of 200.degree. to 300.degree. C.