Polyphenols are chemical compounds found in vegetable, particularly in fruit, having the characteristic of combating free radicals generated within the animal body, studies have shown that fruits produced in high sun exposure regions synthesize a high concentration of these constituents. In this sense the objective of this study was to evaluate the antioxidant capacity of the pulp mandacaru (Cereus jamacaru) fruit native vegetation of Caatinga Northeast of Brazil through the ABTS method. The fruits have been obtained in Teresina, PI, Brazil, in May 2015, then carried to the Bromatology Laboratory of the Federal Institute of Piauí. The extracts, aqueous, ethanol and acetone were extracted from the mandacaru pulp, using respectively Mili-Q water, absolute ethanol (PA) and acetone (PA) under VIEIRA et al., 2011. The antioxidant activity was determined by sequestration free radical ABTS • + [2,2-azino-bis (3-etilbenzotiazolin) -6-sulfonic acid] (RE et al., 1999). All analyzes were performed in triplicate, and the results were expressed as mean and standard deviation, for the comparison of averages, were employed in the analysis of variance (ANOVA) and Tukey test, using Prism 4.0 software (GraphPad). It adopted the significance level of 5% probability (p <0.05). The data has expressed in TEAC value (total antioxidant capacity of Trolox equivalent / g of sample) to the aqueous extracts, alcoholic and acetone respectively 0,87a±0.20, 0,85a ± 0.15, 1,04a±0,17μg / g. The values found are higher than those described by Viera et al., (2011) for bacuri fruit pulp, guava, hog plum, cashew, tamarind and below the pulp acerola. Given these results all extracts were effective at sequestering free radicals ABTS, showing that pulp mandacaru can be singled out as a promising source of natural antioxidants.