This invention relates to novel catalysts, of two distinct types, useful for the catalytic hydroconversion of the 1050.degree.F.+ hydrocarbon material contained in heavy crudes and residua such that the resulting product will be suitable for further processing in conventional refinery operations allowing maximization of clean liquid products. Catalysts, which include Group VIB and Group VIII metals, preferably in admixture, and preferably including a Group IVA metal, notably germanium, having certain critical ranges of physical characteristics inclusive of large uniform pore sizes, are used for the conversion, these having been shown to possess improved catalytic activity and selectivity for the hydroconversion of the 1050.degree.F.+ materials of the heavy feeds and residua. Novel methods are described for the preparation of such catalysts, as well as for use of such catalysts. One of the catalysts, i.e., one having properties inclusive of a large number of pores in the 100-275A pore size diameter range, is particularly suitable as a first stage catalyst and the other, which has properties inclusive of a large number of pores in the 100-200A pore size diameter, is especially suitable as a second stage catalyst for use in processing the effluent of said first stage.