Sida acuta Burm.f. (Malvaceae) is known for its high flavonoid content and potent antioxidant activity.The present study was designated to evaluate the various extracts of Sida acuta burm.f. (Malvaceae) in vitro for its radical scavenging activity,cytotoxicity,short term and long term in vivo anticancer activity.The extracts were evaluated for their anti-cancer activity through DPPH assay, Cytotoxicity by MTT and SRB assays in Vero, HEP-2, A-549 and HeLa cell lines followed by short term toxicity studies on Dalton’s Lymphoma Ascites (DLA) and Ehrlich’s Ascites Carcinoma (EAC) cells.The results showed the significant decrease of the viability of the cells in a concentrationdependent manner. According to the IC50 obtained, the chloroform and toluene extracts of S. acuta showed significant antiproliferative activitywhich was further evaluated in vivo. The results revealed a dose dependent increase in lifespan and mean survival time in the animals treated with chloroform and toulene extracts. However, animals treated with 200 mg/kg dose level showed significant improvement.In conclusion, Sida Acuta burm.f. possesses significant anti cancer potential and needs to be further evaluated by isolating key phytochemicals and investigating the proteins that play a major role in this activity.