Significant amounts of mango by-products, such as peels and seeds, could be considered as a source of bioactive properties and promising applications. The current research was designed to estimate the compositional quality of both mango kernels (MK) and peels (MP), the anticancer activity on human breast cancer cell line (MCF7), human colon cancer cell line (HCT116) and normal cell line (VERO). MK was significantly higher in moisture, crude protein, total lipids and total carbohydrate contents than MP, while MP was significantly higher in ash and crude fiber contents. Ca, K, Na and Mg were the major elements in mango kernels and peels. Total phenols (TP), total flavonoids (TF) and radical scavenging activity (RSA) were, also, determined. The TP in MK and MP was 2829.25 and 2565.21 mg GAE /100 g, respectively. However, the antioxidant activity in MP and MK was 79.11 and 55.33 % respectively. Stearic acid (24.4 %) was the predominant saturated fatty acid in MK while oleic acid (44.34 %) was the main unsaturated one. Ellagic and pyrogallol were the most abundant phenolic acids in both MK and MP extracts through HPLC analysis. The highest flavonoid compound in MK and MP was the hesperidin component. The mixture of MK and MP powders showed a high cytotoxic activity against HCT116 (IC50=45µg/ml) and MCF7 (IC50=58 µg/ml). In addition, the by-products samples showed antioxidant activity on all tested cell lines. As conclusion, this study confirmed that mango by-products could provide a natural source of antioxidant and anticancer molecules and can be used as food additives and therapeutic agents.