The hydrodechlorination (HDCl) process of decachlorobiphenyl (the most chlorinated among polychlorinated biphenyls (PCBs)) promoted by a presulphided NiMo/gamma-Al2O3 catalyst has been studied. The experimental runs were carried out in a stirred batch reactor at constant temperature and pressure using hexadecane as reaction medium, Temperature levels T = 250 and 300 degreesC at hydrogen pressure P-H2 = 20 bar were tested. The kinetic analysis of both the overall hydrodechlorination process (organic chlorine --> inorganic chlorine) and of the partial network (decachlorobiphenyl --> nonachlorobiphenyls --> products) was performed and the corresponding kinetic constants have been evaluated. The HDCl process was completed in about 240 min at T = 250degreesC and in <60 min at T = 300degreesC.