A pair of mesoporous and hierarchical macro/mesoporous alumina-supported catalysts having distinct textural parameters have been chosen to elucidate the effect of texture on activity in hydrodesulfurization (HDS) and hydrodemetallization (HDM) of heavy tatar oil possessing extremely high viscosity and sulfur content. For monitoring catalyst properties, the samples have been investigated by XRD, wXFS, XPS, EXAFS, SEM, TEM, FTIR, TPD-NH3, mercury porosimetry, and: N-2 adsorption methods. Among different factors such as support acidity, active component dispersion, and texture, the last one has been found to play. the most Significant role in this process. The hierarchical macro/mesoporons catalyst shows lower coking rate of the hydrotreated products, as well as higher HDS and HDM conversions despite its lower,active component dispersion and decreased support acidity.