A number of solutions to reduce sulphur in fluid catalytic cracking (FCC) naphtha have been suggested. One of these is to reduce the sulphur content in the FCC reactor by using an FCC catalyst or an FCC catalyst additive. In most of the published laboratory investigations within this field, steam-deactivated, metal-free FCC catalysts have been used. This study discusses the effects of nickel and vanadium present on the FCC catalyst with respect to the sulphur level in FCC naphtha. The effects of these metals are discussed both in the absence and the presence of a sulphur-reduction additive. The study shows that the sulphur level in FCC naphtha is significantly lower when testing with metal-impregnated catalysts as in the case when testing the catalysts in the absence of metals. The study also shows that, when mixed with metal-impregnated catalysts, the effect of a sulphur-reduction additive is prohibited.