Mandacaru (Cereus jamacaru DC. Subsp. Jamacaru) is native to the Brazilian Caatinga and is part of the Cactaceae family. Mandacaru fruits are attractive in taste and flavour, although they are not widely commercialised. However, there is limited scientific literature on the composition of this fruit. Therefore, the present work was aimed at analysing the physicochemical composition, as well as in vitro antioxidant activity, phytochemical profile, and cytotoxicity of mandacaru fruit from three different locations in the Brazilian State of Sergipe. The pulp and peel of mandacaru fruit used in this study presented low Vitamin C concentration, mean values between batches 18.2 mg. 100 g -1 (pulp) and 27.5 mg. 100 g -1 (peel). The pulp of mandacaru fruit from the region of Monte Alegre presented the highest concentration of apparent phenolic compounds (117.2 mg. EAG g -1 ) and antioxidant activity evaluated by the inhibition of the ABTS radical (22.4 μmol. trolox g -1 ). The chemical profile of mandacaru fruit consisted of o-coumaric and p-coumaric acids, but they were not considered to be cytotoxic; thus, this native fruit is suitable for consumption, exhibiting relevant amounts of apparent phenolic compounds and antioxidant activity. Further studies are needed to prolong the shelf life of the fruit for commercialisation.