this work aimed to obtain and investigate the properties and composition of extracts from flowers of acacia mearnsii; this tree is widely cultivated because the bark is used as a raw material for various industry segments, but the flowers are not yet explored. the essential oil was evaluated by gc/fid, gc/ms, and gc/o. the antioxidant activity (dpph and phosphomolybdenum methods) and chemical composition were investigated for a water-soluble extract, a by-product of the extraction process. 85.8% of the compounds present in the essential oil were identified, 8-heptadecene being the major compound. the main scents detected by the olfactory analysis were roast nutty, coffee, sweet, and floral. the water-soluble extract showed antioxidant activity that may be related to phenolic compounds. results obtained from the lc-qtof/ms analysis have shown that 25 likely flavonoids, such as naringenin, myricetin, quercetin, and rutin are present in the extract.