The catalytic hydrotreatment of chlorobenzene-thiophene mixtures has been studied using a Ni-Mo/gamma-Al2O3 sulphided catalyst. Experimental runs were carried out in a batch reactor at constant temperature (T = 300-320-340 degrees C) and hydrogen pressure (P = 40 bar). The reaction medium was hexadecane. The experimental results show that chlorobenzene hydrodechlorination and thiophene hydrodesulphurization are not inhibited when chlorobenzene and thiophene are hydrotreated in admixture. The results that were obtained are of importance for the development of the hydrodechlorination (HDCl) process of chlorinated liquid wastes contaminated by other organic compounds.