Underused crops have been expanding in the market due to their nutritional and antioxidant characteristics. Lulo, or naranjilla, can be considered an underused crop because it is grown on a small scale in Colombia and has high nutritional value. The edaphoclimatic conditions of cultivation of this fruit can influence its post-harvest characteristics. Thus, the objective of the work was to evaluate the antioxidant activity and the physicochemical characteristics of lulo fruit obtained from cultivation in Brazil. The post-harvest variables analyzed were antioxidant activity by ABTS, DPPH, FRAP methods, phenolic compounds, flavonoids, lycopene, β-carotene, ascorbic acid, and physicochemical characteristics of acidity, soluble solids, and ratio. The FRAP antioxidant activity method showed 81.40 mg Ferrous Sulfate g-1 (dry mass), ABTS 57.00 mg Trolox g-1 (dry mass) and DPPH 14.40 mg Trolox g-1 (dry mass). The flavonoids contents were 1.00 mg Quercetin g-1 (dry mass), which is considered low. Lulo fruit showed to be a good source of β-carotene (7.00 mg 100 g-1), lycopene (3.57 mg 100 g-1) and ascorbic acid (57.71 mg 100 g-1). The fruit is acidic (2.29 g Citric Acid 100 mL-1), with low soluble solids content (5.12%) and low ratio (2.25). This work showed that the lulo fruit obtained from cultivation in São Paulo (Brazil) is a potential source of natural antioxidants and can be interesting for the processing and diversification of Brazilian products.