A process for catalytic cracking of a hydrocarbon feedstock feeds to produce an enhanced yield butylenes and isobutane comprises contacting the feedstock with a catalyst composition comprising MCM-68. The MCM-68 may be used as the primary cracking catalyst or may be used as an additive component in conjunction with a conventional cracking catalyst, such as a large pore molecular sieve having a pore size greater than 7 Angstrom.