Abstract: A process for selective catalytic cracking of a petroleum-based feedstock to produce a product having a high yield of liquified petroleum gas (LPG) and light olefins having 3 to 4 carbons includes providing a fluidized bed reactor which is a high velocity riser, continuously circulating fluidized bed reactor; providing a solid acidic catalyst comprised of: from 1 to 6% by wt. of ultra stable Y-zeolite; from 8-25% by wt. of Pentasil zeolite which is shape selective; from 0-8% by wt. of an active material which is bottom selective; from 0-1% by wt. of rare earth constituents; and from 91 to 60% by wt. of nonacidic constituents and binder; charging the fluidized bed reactor with the solid acidic catalyst and the petroleum-based feedstock; and cracking the petroleum-based feedstock in the presence of the solid acidic catalyst in the fluidized bed reactor. The reactor is operated at a Weight Hourly Space Velocity (WHSV) ranging from 40 to 120 hr.sup.