Yerba mate (YM) is a native from South América with regional importance. This study aims to obtain an YM ultrasound-assisted extract and evaluate its antioxidant activity and phenolic compounds. Two samples of YB were obtained by different municipality: (1) Cascavel - PR; and (2) of Santa Maria do Oeste - PR. The YM (80 g) were extracted with ethanol: water mixture (70:30; 4 L) using an ultrasound bath (70 ºC, 80% power, 37 kHz frequency for 60 min). The extract was filtered and spray drier (flow rate 0.5 L/h; 1.2 mm nozzle; inlet air 140 ºC). The antioxidant activity of YB was evaluated by ABTS and DPPH assays, and by total Phenolic Compounds. The ABTS, DPPH, and phenolic compounds were determined spectrophotometrically at 734, 517, and 725 nm. For ABTS, the values obtained were (1) 37.4 ± 5.0 and (2) 53.6 ± 6.7 (g equivalent Trolox/100 g). For DPPH, the IC50 results were (1) 9.61 ± 1.41 and (2) 9.33 ± 0.681 (µg DPPH/mL extract). Finally, the total phenolic compounds were (1) 11.23 ± 0.81 and (2) 10.65 ± 0.62 (g gallic acid/100g sample). The YM 2 extract had a higher antioxidant activity by ABTS, however both samples had a similar IC50 and phenolic content values (Tukey test, p < 0,05). For YM ultrasound-assisted extract obtained under the same condition evaluated here, Tonet found lower DPPH (IC50 = 7.91 ± 0.06 µg DPPH/mL extract). For YB leaves collected along six months, Silva obtained higher phenolic compounds values (15 to 17 g gallic acid/100 g sample). This study demonstrates the suitability of ultrasound-assisted YM extract obtention and its antioxidant potential, probably associates with its phenolic compounds. The YM source may interfere the antioxidant activity, as observed for ABTS values.