The strong growth of biodiesel production occurring in the last years has determined the availability of a great amount of the byproduct glycerol. Many researches in the world are therefore oriented to find new possible uses for glycerol also with the aim of reducing the cost of biodiesel. In this paper the chlorination of glycerol with gaseous hydrochloric acid to obtain 1,3-dichlorohydrin and then epichlorohydrin will be described. All the advantages of this process will be examined and discussed. The behavior of the different proposed catalysts (normally compounds containing carboxylic acid groups), the reaction kinetics, the effect of the catalyst concentration, the effect of HCl pressure, the vapor−liquid phase equilibria of the reaction products in the reaction environment, and the most convenient operative conditions have been studied, concluding with useful suggestions for the design of the industrial plants.