MoNi/Al2O3 catalysts have been widely used for hydrodesulphurisation of oil fractions. In order to enhance the catalytic activities for HDS and HDN, catalysts supported on titania-modified alumina carriers have been studied. The MoNi/Al2O3-TiO2 catalysts were characterised by benzene sorption, ammonia sorption, temperature programmed reduction, X-ray diffraction and scanning electron microscopy. The supports effect was examined by comparing thiophene conversion and sulphur or nitrogen contents in diesel oil fraction.