Abstract: A process for the catalytic hydroconversion of special petroleum feedstocks, containing 10-28 W % asphaltenes, and having Ramsbottom carbon residue of 12-35 W %, such as Cold Lake and Lloydminster crude and residua materials. In the process, high percentage conversion (65-80 V %) to lower boiling hydrocarbon products can be achieved by maintaining a narrow range of reaction conditions, preferably in an ebullated bed catalytic reactor. Reaction temperature is 780.degree.-835.degree. F., hydrogen partial pressure is 2000-3000 psig, and space velocity is 0.25-5.0 V.sub.f /hr/V.sub.r. Higher conversion of about 80 to 95 volume percent can be obtained with recycle of 975.degree. F..sup.+ vacuum bottoms fraction to the reactor. Useful catalysts have total pore volume of about 0.5-0.9 cc/gm and include cobalt-molybdenum and nickel-molybdenum on alumina support.