The liquid extracted from cashew-nut shell is composed almost completely of phenolic compounds containing 15-carbon chains with variable unsaturation degrees, meta-substituted in the aromatic ring. The similarity of these compounds with the structures described as efficient peptizing agents for asphaltenes, the crude oil polar fraction, induced us to evaluate cashew-nut shell liquid (CNSL) and its derivatives, cardanol and polycardanol, as asphaltene stabilizing agents. The results confirm that CNSL and cardanol have a performance comparable to nonylphenol. Polycardanol was not only less efficient than its monomer, but, instead, enhanced the precipitation of asphaltenes. This effect may be ascribed to the large number of phenol groups present in the polymer that may flocculate the asphaltene particles or increase its polarity, reducing its solubility in aliphatic solvents.