The vapor phase isopropylation of quinoline was carried out over HY and modified HY zeolites in a fixed-bed reactor at atmospheric pressure. The yield of 2-isopropylquinoline was higher over modified zeolites, especially over doubly-promoted LaKHY zeolite. The maximum yield of 2-isopropylquinoline obtained was 48.8 wt% with 82.9% selectivity. The reaction favors on moderate Lewis acidic sites.