A process for preparing an improved slurry catalyst for the upgrade of heavy oil feedstock is provided. The process comprises providing at least a metal precursor in solution comprising at least two different metal cations in its molecular structure, with at least one of the metal cations is a Group VIB metal cation; sulfiding the metal precursor with a sulfiding agent in solution forming a catalyst precursor; and mixing the catalyst precursor with a hydrocarbon diluent to form the slurry catalyst. In one embodiment, the at least a metal precursor comprising at least two different metal cations is prepared by combining and reacting at least one Group VIB metal compound with at least a Promoter metal compound selected from Group VIII, Group IIB, Group IIA, Group IVA metals and combinations thereof.