Abstract. Catalytic cracking of durene over HY and Hβ zeolites, and their silica modified forms such as 30% SiO 2 /HY, 30% SiO 2 /Hβ, and 10% SiO 2 /ZSM-5 was examined at 450 C. Both HY and Hβ zeolites showed higher than 90% conversion, but 10% SiO 2 /ZSM-5 around 30% conversions. Both the 30% SiO 2 /HY and 30% SiO 2 /Hβ displayed slightly lower conversion than the respective parent zeolites, but higher selectivity to p-xylene. This study establishes that for durene cracking large pore zeolites are better than medium pore zeolites. Time on stream study showed decrease of conversion with the increase in time due to coke formation, insisting frequent activation of catalyst. This study depicts that other large pore zeolites could also be good to crack durene to p-xylene.