In our study the antioxidant activity of fresh and stored beers, produced exclusively from barley malt and with 10 and 30% of maltose syrup, was evaluated. Beers were stored for 1, 2, 3 months at 25°C. Antioxidant activity was measured by DPPH and FRAP assays. FRAP evaluates the ability to reduce the Fe (III) complex to Fe (II) (reducing activity), whereas DPPH assesses the reduction by antioxidants of free radical DPPH˙+ (antiradical activity). The content of polyphenols in beers was also analysed. We observed that the use of maltose syrup as adjunct resulted in lower beer antiradical and reducing activities as well as the concentration of polyphenols. The decreases in beer antiradical and reducing activities and the concentration of polyphenols were also found during beer storage. The higher use of maltose syrup the higher reduction of beer antiradical and reducing activities and the concentration of polyphenols during storage.