An unsteady-state kinetic model of both benzene hydrogenation (HDA) and thiophene hydrogenolysis (HDS) on a sulfide hydrotreating catalyst Ni-Mo/Al 2 O 3 has been developed. The model adequately describes experimental data obtained at the pressure 2 MPa, temperature 573 K and at various contact times and ratios of benzene/thiophene. The model is based on the assumption that the catalyst surface contains only one type of active sites, i.e., Ni atoms in the sulfide bimetallic species, which are responsible for both hydrogenolysis and hydrogenation reactions.