High surface area metal-containing catalysts are prepared by dispersing a thermally decomposable metal compound in a hydrocarbon oil having a Conradson carbon content of up to about 50 weight percent, the thermally decomposable metal compound being added in an amount sufficient to obtain a specified ratio of atoms of Conradson carbon of the oil chargestock to atoms of metal constituent of the thermally decomposable compound, heating the compound in the presence of a gas comprising either hydrogen or hydrogen sulfide or hydrogen and hydrogen sulfide to form a solid high surface area catalyst within the oil, and recovering the resulting high surface area catalyst. The metal constituent of the thermally decomposable metal compound may be a metal of Groups II, III, IV, V, VIB, VIIB, VIII or mixtures thereof. The high surface area solids are suitable as catalysts, catalyst supports or catalyst components for use in hydrocarbon treating processes and in chemical processes.