Additives to a zeolite-containing cracking catalyst were synthesized and studied in order to enhance the resistance to the poisoning effect of nitrogen compounds (in particular indole) upon cracking of n-undecane as the model FCC hydrocarbon. The additives were represented by acid-activated clays and mixed oxides. The activation of clays in the catalyst by 5% sulfuric acid solutions was shown to enhance the resistance to nitrogen. The introduction of Mg, Al - mixed oxides in the catalytic system in the amount of 10 wt% increased its activity and resistance to indole. The highest resistance was observed for the systems containing magnesium-aluminum oxides with a Me-2+ to Me3+ molar ratio equal to 0.5: 1. Cobalt modification of these mixed oxides enhanced the activity and nitrogen resistance of the cracking catalysts. Use of such nitrogen-resistant catalysts will allow cracking of heavy raw materials.