A desirably upgraded charge stock for catalytic cracking containing a relatively large proportion of heavy hydrocarbons boiling above about 800.degree. F., is produced by first subjecting a raw feedstock boiling predominantly above 600.degree. F. and containing a substantial proportion of material boiling above 800.degree. F., to catalytic hydrofining followed by catalytic hydrocracking at high pressures in the presence of a Group VIB and/or Group VIII metal-promoted, crystalline zeolite hydrocracking catalyst. The hydrocracking catalyst and conditions are chosen so as to achieve selective conversion of material boiling between about 600.degree. and 800.degree. F. to lower boiling materials with a relatively minor conversion of the 800.degree. F+ material. The resulting product boiling above 400.degree. F is rich in 800.degree. F+ material, and constitutes an excellent catalytic cracking charge stock.