This study was aimed to investigate the phytochemical constituents, antioxidant and anti cancer potential of Costus pictus D.Don leaf extracts. Three different solvents ethanol, petroleum ether and aqueous were used for extraction. Phytoconstituents of the extracts were analysed by standard methods. DPPH, FRAP and Total antoxidant activity are the methods used for investigation of antioxidant potential of different extracts of C.pictus leaves. Anti cancer potential of leaf extracts were studied against breast cancer cell lines (MCF-7). Phytochemical analysis revealed the presence of active ingredients such as Alkaloids, Steroids, Terpenoids, Glycosides, Tannins, Saponins, Phenols, Flavonoids and Proteins. The extracts had significant antioxidant and free radical scavenging activity. Treatment with ethanol, aqueous and petroleum ether extracts of Costus pictus leaf extracts decreased the growth rate and cell survival of MCF-7 cells. Our study suggests that bioactive compounds present in Costus pictus leaves could provide new leads to the development novel drugs for the management of oxidative stress related diseases.