Soybean (Glycine max L.) is an important worldwide crop, mainly used as raw material for oil production, and the residue is mainly used as feedstuff. The medicinal functions of consuming soybean have been shown to be effective against number of chronic diseases such as cancer, heart disease, osteoporosis and menopausal symptoms. The objective of this work was to evaluate isoflavone and phenolic content and their antioxidant activity in three Egyptian soybean cultivars Giza 22, Giza 35 and Giza 111. Significant differences among the studied cultivars were found for genistein, daidzein, glycitein and total isoflavones due to genetic effects since all cultivars were collected at the same location. The total isoflavones ranged from 470.6 mg/100 g dry soybean (Giza 22) to 200.3 mg/100 g (Giza 111). The rank of total phenolic content (TPC) was Giza 22 > Giza 35 > Giza 111. At a concentration of 10 mg/mL, the free radical scavenging (antioxidant) capabilities were 79.34, 65.97 and 59.35 % for the extracts of Giza 22, Giza 35 and Giza 111, respectively. In conclusion, the present study or related studies are of great importance to identify the best soybean cultivar with the highest isoflavone content to be used as source for production of nutraceutical products rather than as a nutritional source of protein.