A process is provided for the chlorination of aliphatic hydrocarbons containing 1 to 4 carbon atoms using hydrogen chloride as the source of chlorine. The process comprises reaction steps operated in tandem in separate zones. First, an unsaturated aliphatic fluorocarbon is oxychlorinated to give the corresponding saturated perchlorofluorocarbon and water, and second, the saturated perchlorofluorocarbon is reacted in the vapor phase with a hydrocarbon to produce the desired chlorinated hydrocarbon, hydrogen chloride and the unsaturated aliphatic fluorocarbon, third, hydrogen chloride and unsaturated aliphatic fluorocarbon are separated from the chlorinated hydrocarbon and recycled to the first step, and fourth, the chlorinated hydrocarbon is further purified by subjecting it to addition chlorination to convert traces of unsaturated aliphatic fluorocarbon to the corresponding saturated perchlorofluorocarbon, which is separated and recycled to the second step.