Separation of molybdenum from the synthetic chloride leach liquors of spent hydrodesulphurization catalysts was studied by employing cationic (Diphonix) and anionic resins (AG1-x8). The composition of the solution was Mo 394 ppm, Co 119 ppm and Al 1782 ppm. In the HCl concentration range from 1 to 6 kmol/m³, the loading of Co and Al was negligible. As the concentration of HCl increased, the loading percentage of Mo by AG1-x8 increased, while that by Diphonix decreased. The Mo in the loaded AG1-x8 was successfully eluted by using NaOH solution. In terms of the possibility of producing Mo compound from the eluant, AG1-x8 was found to be better than Diphonix. The loading capacity of AG1-x8 for molybdenum was determined. Column experiments verified that it was possible to separate Mo from Co and Al by ion exchange with AG1-x8.