A process is disclosed for treating a charge hydrocarbon such as a naphtha or middle distillate hydrocarbon containing undesired aromatic components, sulphur and nitrogen compounds. The process comprises:
   maintaining a bed of metal sulphide catalyst comprising a non-noble metal of Group VIII and a metal of Group VIA on a carbon support;
   passing a charge hydrocarbon feed in the presence of hydrogen into contact with said metal sulphide catalyst at hydrotreating conditions in order to effect hydrodearomatisation, hydrodesulphurisation and hydrodenitrogenation of said charge hydrocarbon containing undesired aromatic components, sulphur and nitrogen compounds;
   forming a product stream of hydrocarbon containing lesser quantities of undesired aromatic components, sulphur and nitrogen, and
   recovering said product stream.
The process is characterised in that the carbon support is a phosphorus-treated carbon support prepared by heat treating mixtures of activated carbon and phosphorus compounds at temperatures greater than 450°C. It is further characterised in that the phosphorus in the phosphorus-treated carbon support exists predominantly as polyphosphate species bound to the carbon surface, being characterised by peaks between -5 and -30 ppm in the solid-state magic angle spinning ³¹P nuclear magnetic resonance spectrum.