Abstract: A tri-elemental catalyst suitable for hydrocracking and hydrogenation of aromatics-containing petroleum hydrocarbon feedstocks such as hydrotreated cracked feedstock, virgin feedstock, vacuum distillate, middle distillate, mixtures thereof, and the like, is disclosed. The catalyst is suitable for hydrodesulfurization as well as hydrodenitrogenation, thus the feedstock can contain sulfur and nitrogen in addition to the aromatic components. Hydrocracking and aromatics hydrogenation of the petroleum hydrocarbon feedstocks is accomplished under a relatively wide range of process conditions using the tri-elemental catalyst that contains a catalytically active metal phase constituted by a Group VI-B element, a Group VIII first transition series element and a Group VIII second transition series element, all supported on a titania-alumina support containing about 5% to about 30% by weight titania in the support.