Disclosed is a process wherein a two-stage hydroconversion process for converting a heavy hydrocarbonaceous feedstock to lower boiling products which process comprises: (a) reacting the feedstock in a first reaction stage at hydroconversion conditions which include temperature from about 650.degree. F. to 900.degree. F., and hydrogen partial pressure ranging from about 50 to 5000 psig in the presence of a metal compound which is convertible to a solid, non-colloidal, metal-containing catalyst, said metal selected from the group consisting of metals from Groups IVB, VB, VIB, VIIB, and VIII, of the Periodic Table of the Elements, wherein said metal compound is: (i) soluble in the hydrocarbonaceous feed; or (ii) soluble in an organic medium that can be dispersed in the hydrocarbonaceous oil, or (iii) soluble in water resulting in an aqueous solution which can then be dispersed in the hydrocarbonaceous feedstock; (b) passing the resulting product stream to a second reaction stage where it is reacted under slurry hydrotreating conditions which include: (i) temperature in the range of 650.degree. F. to 750.degree. F., with the promise that this slurry hydrotreating stage be operated at a temperature at least 25.degree. F. less than the first stage, and (ii) hydrogen partial pressures in the range of 800 to 4000 psig, and in the presence of hydrogen and a hydrotreating catalyst comprised of at least one Group VI metal and at least one Group VIII catalyst, on an inorganic oxide support.