Brown algae (BA) belong to the group Heterokontophyta, a large group of eukaryotic organisms distinguished most prominently by having chloroplasts surrounded by four membranes. In Egypt, brown algae are naturally spread over large areas of marine beaches. The present study aims to determine the bioactive compounds and biological activities in BA collected from the shores of the Egyptian seas. Data indicated that carbohydrates were the largest compound (60.59%) followed by ash (19.45%), crude fiber (7.14%), total protein (4.02%) and crude fat (0.82%.). Also, polysaccharides were the largest compound followed by phenolics, tannins, carotenoids and flavonoids. β-carotene assay (BCA) indicated that ethanol extract (EtE) recorded the highest antioxidant activity followed by methanol extract (MeE) and water extract (AqE). The values of EtE extract are coming well i.e. closing to the line of 50 mg α-tocopherol followed by MeE and AqE, respectively. Also, MeE possessed the highest free radical scavenging activity (FRSA). For Half-maximal inhibitory concentration )IC50(, the AqE, EtE and MeE recorded 19.92, 10.41 and 12.52 μg/mL, respectively. The IC50 of BHT (standard) was 7.78 μg/mL. The BCA and FRSA of different tested extracts and standard was in the following order: standards (BHT/ α-tocopherol) > EtE > MeE > AqE. In conclusion, Brown algae extracts (BAE) contains several classes of phytochemicals with other compounds that are responsible for different biological activities including antioxidant and radical scavenging activities. Therefore, we recommended like of that algae extracts (BAE) to be included in daily diets, drinks, food supplementation and pharmacological formulae.