There is growing interest in the potential role of bioactive ingredients from agro-industrial wastes, such as the soybean milk that also called Okara (O). In this study, we investigated the biological efficacy of milk supplemented with okara (M:O) at three different ratios (100: 0, 80: 20, and 70:30) to improve their nutritional and biological properties levels. The results indicated an enhancement in the phenolics and flavonoids contents in okara due to supplementation, the antioxidants capacity determined with ABTS and DPPH, and the anticancer activity against three cancerous cell lines including, Human breast MCF-7, colon HT-29, and prostate PC3 cancer cell lines as well as one non-cancerous normal breast MCF-12F cell lines. The effect of milk supplemented okara showed an increase in antioxidant activity relative to the supplementation ratio. Moreover, the Total phenolic TPC and flavonoid contents TFC analysis showed an increase in the milk TPC and TFC contents after supplementation. In addition, okara enhances the anticancer activity against tested cancer cell lines. The results indicated a ratio-dependent effect in all tested cell lines. Surprisingly, milk supplemented with okara at a 20% ratio displayed the highest anti-proliferation activity of MCF-7 compared to a 30% ratio. No significant cytotoxic effect was observed due to MCF-12F. Moreover, the oxidative stress enzymes including SOD, CAT, GSH, and GPx Were determined. The results indicated an increase in the enzyme activity of supplemented milk. The mode of action was also evaluated using gene expression of pro and anti-apoptosis key markers Caspase-3, P53, Bax, and BCl-2. The data indicated that all pro-apoptosis markers were upregulated when the anti-apoptosis marker BCL-2 was downregulated. It was concluded that fortification of dairy products with 30 % Okara enhances physical and biological activity and health-promoting products.