Recent studies show that chabazite can catalyze cracking reactions and remove nitrogen and heavy metals from bitumen derived from oil sands. In this study, it was found that, after reaction at 400 degrees C for 1 h, indole concentration was reduced by 43% and nitrogen removals up to 17% were obtained. Pyridinic nitrogen containing compounds were also found to react in the presence of natural zeolites although the reaction rates are much slower. Experimental evidence suggests that indole is converted into aniline and the nitrogen removed remains on the surface of the catalyst as aniline or aniline derivatives. Two possible reaction paths for the conversion of indole into aniline are presented. Experimental evidence suggests that the water affects the nitrogen adsorption but not the reaction pathway. A better understanding of the reaction path and adsorption phenomena of this system may lead to an improved process for heavy oils.