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Recebido em 6/4/05; aceito em 14/9/05; publicado na web em 16/2/06 RECOVERY OF ELEMENTS FROM SPENT HYDROREFINING CATALYSTS AFTER FUSION WITH KHSO 4. This work describes a process for metal recovery from spent NiMo and CoMo/Al 2 O 3 commercial hydrorefining catalysts. The samples were treated by fusion with potassium hydrogen sulfate (5 h, 600 o C) with a KHSO 4 /catalyst mass ratio of 10:1. After fusion the solid was solubilized in water (100 o C), leaving silicon compounds as residue. Losses of nickel and cobalt may reach 16 wt% of the amount present in the sample, depending on the silicon content. Soluble metals were isolated by selective precipitation techniques (nickel, cobalt, aluminum) or by solvent extraction with methyl-isobutyl ketone (molybdenum) in a hydrochloric acid medium. All metals were recovered in very good yields except for nickel and cobalt in the presence of considerable amounts of silicon. Soluble wastes consist of potassium/ sodium sulfates/chlorides. Solid wastes correspond to about 4 wt% of the catalyst and can be discarded in industrial dumps.