A multi component catalyst and catalytic cracking process for selectively
producing C.sub.3 olefins. The catalyst comprises a first molecular sieve
having an intermediate pore size, a second molecular sieve and,
optionally a third molecular sieve having a large pore size. At least one
of the channels of the second molecular sieve has a pore size index that
is less than the pore size index of at least one channel of the first
molecular sieve. The process is carried out by contacting a feedstock
containing hydrocarbons having at least 5 carbon atoms is contacted,
under catalytic cracking conditions, with the multi component catalyst.
The catalyst finds application in the cracking of naphtha and heavy
hydrocarbon feedstocks.