Supported nickel phosphides were prepared by treating an amorphous Ni-B alloy on silica-alumina support with phosphine (15 vol.% PH3/H2) at relatively low temperature. The amorphous Ni-B/SiO2-Al2O3 precursors were synthesized by silver-induced electroless plating. The amorphous precursors and catalysts were characterized by X-ray diffraction, high-resolution transmission electron microscopy, selected area electron diffraction, BET surface area and inductively coupled plasma measurements. The transmission electron micrographs of the Ni2P/SiO2-Al2O3 particles with their size ranging from 60 to 80 nm showed that they were homogeneously dispersed over the SiO2-Al2O3 support. The as-prepared catalysts exhibited an excellent catalytic activity in the hydrodesulfurization (HDS) of dibenzothiophene.