The effect of vegetable oil unsaturation on the distribution and composition of the products of oil conversion over an equilibrium cracking catalyst was studied. Co-conversion of vacuum gas oil and vegetable oils under catalytic cracking conditions make it possible to increase the yield of gasoline fraction by 10 wt.%. A maximum promoting effect is attained by the addition of 5-10 wt.% vegetable oil. Investigation of joint transformations of n-undecane, tetralin and sunflower oil upon cracking revealed that an increase in the yield of gasoline fraction can be related to the occurrence of hydrogen transfer reactions and manifestation of the competitive sorption effect. (c) 2012 Elsevier Ltd. All rights reserved.