Hymenaea courbaril L. var stilbocarpa (jatoba) bark has been reported to be a great natural source of phenolic compounds. The important role of phenolics in human health has been demonstrated, thus increasing the interest in such products and their demand by consumers. Ultrasound-assisted extraction (UAE) was used to improve extraction efficiency in terms of extraction time and total polyphenol content. A preliminary study was first conducted to determine the type of solvent and optimum S/F (solvent volume to feed mass ratio) to be used in subsequent experiments. Water with an S/F of 20 was found to be the best solvent for the extraction of phenolic compounds. The UAE extractions were carried using a maximum and minimum ultrasound power (60 and 20 W) for 40 min at 50 ˚C and compared with conventional agitation extraction (AGE). A statiscally significant (P < 0.05) effect of ultrasound, was observed (approximately 15 % increase in total phenolic compounds content) when using maximum power; moreover, the three-stage and scaled-up ultrasound experiments demonstrated the efficiency of this process. DPPH analysis confirmed the high antioxidant activity of the ultrasound extracts and HPLC analysis demonstrated that besides in terms of quantity ultrasound irradiation alter the extract composition, supporting the suitability of UAE for the preparation of antioxidant-rich plant extracts.