Improved catalytic cracking

Octane and overall product quality improvement in catalytic cracking processes utilizing an essentially entirely amorphous cracking catalyst can be attained by using instead a catalyst comprising a minor amount, e.g. from about 0.01 to about 25 weight percent, of a class of crystalline zeolites characterized by a silica to alumina mole ratio greater than about 12 and a constraint index of about 1 to 12. The crystalline zeolites may be added to the conventional amorphous cracking catalyst in the cracking process by way of adding a separate additive composition in an amount which provides the zeolite component of the additive composition in said minor amount of the total catalyst in the cracking process.