This study developed a methodology for converting hydrogenated cardanol, a compound extracted from cashew nut shell liquid into compounds with structural characteristics of antioxidants similar to the ones used in products derived from petroleum. The intended changes were carried out through exhaustive alkylation with tert-butyl chloride. The performance of the products was estimated in terms of oxidative stabilization during storage of cracked naphtha samples collected from the outlet of an industrial unit. The compound 2,4,6-tri-t-butyl-pentadecylphenol (new antioxidant) has presented a better efficiency in the storage assays as compared to the commercial additive used as reference in the refinery at the moment of sampling. (C) 2003 Published by Elsevier Science Ltd.