Two categories of FCC catalysts were prepared. The first one is an FCC catalyst containing Y-zeolite and amorphous matrix. The second category is amorphous catalyst without Y-zeolite. Alumina was systematically added to both catalyst categories, The addition of alumina to the FCC catalyst containing Y-zeolite forms an active matrix. The inactive matrix of the catalyst is composed of kaolin filler and silica sol binder. The experimental data clearly show that alumina addition to both catalyst categories substantially increased both catalyst surface area and acidity, The addition of alumina to the amorphous catalyst resulted in a significant increase in hydrotreated VGO conversion. However, similar alumina addition to Y-zeolite containing catalysts did not appear to have a significant effect on the hydrotreated VGO conversion.