Bran is a byproduct obtained after the milling of cereal grains and is a reservoir of nutrients, vitamins, minerals, phytochemicals, and antioxidants which are very important for disease prevention and health promotion. The current work was planned to evaluate the chemical composition, phytochemical profiling, and antioxidant potential of native and modified brans of wheat, corn, barley, millet, sorghum, and oat. These brans were subjected to fermentation by yeast and lactic acid bacteria, autoclaved, size reduction (1 mm and 2 mm particle size), enzyme modifications using cellulase and xylanase. In vitro antioxidant properties were evaluated by DPPH free radical scavenging activity and ferric reducing antioxidant power (FRAP) assay, whereas total phenolic content (TPC) and total flavonoid content (TFC) were also determined. The maximum quantity of TPC was found in xylanase treated oat bran 0.364 +/- 0.026 mg GAE g-1. The maximum amount of TFC was found in 1mm sorghum bran 211.70 +/- 0.09 mu g g-1 QE. Whereas increased DPPH free radical scavenging rate was recorded in cellulase treated sorghum bran 87.49 +/- 0.11%. Furthermore, the maximum FRAP values were found in 1mm sorghum bran (710.49 +/- 0.17 mu M FeSO4 g-1). The most effective modification treatments were enzyme modification and size reduction. Study results indicated that modified cereal brans might be important for the development of innovative and unique functional foods as well as could be used for the prevention and treatment of various disorders due to their antioxidant properties.