NiMo/B-Al2O3 catalysts for VGO hydrotreating differed in peptizing agent for supports preparation (nitric acid or ammonium solution) have been studied. The molar ratio of HNO3/Al2O3 = 0.03 and NH3aqua/Al2O3 = 0.09 and 0.15 were used. Supports and catalysts were studied by the nitrogen and mercury adsorption, IR-spectroscopy of adsorbed CO, XRD, 11B and 27Al NMR, UV-vis DRS, HRTEM, XPS. NiMo/B-Al2O3 catalyst peptized by ammonia at molar ratio of NH3/Al2O3 = 0.09 contains higher amount of NiMoS phase than catalysts peptized by nitric acid. Boron catalyst based support peptized by nitric acid is characterized by active component particles with lower slab length. Simultaneous presence of ammonia and boron results in increase of the slab length of active component, while stacking number decreases. According to the results of catalytic testing in HDS of DBT, boroncontaining catalysts are more active. However, NiMo/B-Al2O3 catalyst obtained using ammonia with molar ratio of NH3/Al2O3 = 0.09 has higher activity in HDS of DBT in comparison with NiMo/B-Al2O3 catalyst obtained using nitric acid. Testing in VGO hydrotreating confirmed that utilization of ammonia as a peptizing agent for support preparation significantly improves the activity of boron catalyst in HDS and HDN reactions.