The hydrocracking reaction pathways and kinetics of alkyl aromatic structural elements present in typical petroleum feedstocks were probed through experiments at 350 degrees C and 1000 psig of hydrogen pressure with a Shell NiW/USY zeolite catalyst. Experimental results for C4-C15 alkylbenzenes provided insight into their respective alkane-like and aromatic-like character, as well as the effect of side-chain length on the kinetics and product selectivities. Initial product selectivities indicated that the expected prototypical ring dealkylation to benzene was accompanied by other significant reactions. Reactions in the side chain produced various shorter-chain alkylbenzenes, including toluene. Ring closure of the side chain was also significant, producing hydroaromatic bicyclic compounds. The overall reaction rate was first order and generally increased with increasing alkyl side-chain length.