The present invention concerns a novel additive composition for reducing sulfur content of a catalytically cracked gasoline fraction. This additive composition comprises a support consisting of porous clay into which a first metal from group IVB is incorporated and a second metal from group IIB is impregnated. Preferably, the first incorporated metal is zirconium and the second impregnated metal is zinc. The sulfur reduction additive is used in the form of a separate particle in combination with a conventional cracking catalyst in a fluidized catalytic cracking process to convert hydrocarbon feed stocks into gasoline having comparatively lower sulfur content and other liquid products.