Abstract: Since time immemorial, edible mushrooms have been closely associated with the food habit of a large population of this world mainly belonging to ethnic and tribal groups, not only for its delicious earthy flavour but also it acts as a healthy supplements. Besides highly nutritive, mushrooms possess several chemically diverse groups of biologically active secondary metabolites mainly belong to phenolic, flavonoids,1 β-glucan,2 heteropolysaccharides,3 glycosides, saponin, terpenoids groups4 etc which are beneficial to health. So mushrooms can be appropriately called “Gift of the God” or “the pharmaceutical store-house of nature’’. Mushrooms can grow very easily during the growing season and it is cultivated also in mass amount nowadays, so they are easily available. Those novel bioactive compounds from mushrooms have shown several pharmacological activities like anti-oxidant,5 antimicrobial,6 anticancer,7 immuno-modulatory,8 anti-diabetic,9 anti-ulcer,10 cardio-protective11 and hepato-protective12 etc. Free radicals are extremely reactive and highly unstable molecules with an unpaired electron. Free radicals can steal or donate electrons from several sources like DNA, lipid of the cell membrane and proteins etc to get stability and overtime cause oxidative damage accumulation to the cell that is responsible for several diseases like cancer, neurodegenerative diseases, and ageing, etc. Free radicals are produced as a by-product of normal metabolic processes like respiration or from other external sources like cigarette smoking, x-rays, polluted air, and industrial chemicals, etc. To combat the gener ation of oxidative stress exogenous anti-oxidant is necessary to neutralize the ROS.13 Cancer, one of the most potent and dangerous ancient disease. It is of several types like lung, breast, colon, skin, blood cancer etc, all of which share a common characteristic-the uncontrolled proliferation and growth of cells. According to the report of the International Agency of Research for Cancer ( IARC), cancer will be rise by about 50% in the next twenty years.14 Although the rate of mortalities can vary from cancer to cancer, some of which are really fatal like lung cancer with a death rate of about 70%,followed by colon cancer (50%) and breast cancer (17%), prostate cancer (13%) in the United State in 2013.15 The aim of our present study is to access the anticancer and anti-oxidant potential of a wild edible mushroom Macrocybe crassa belonging to division Basidiomycotina. A lot of investigation has been already done on anticancer activity of mushrooms and the observations informed that several gifted mushrooms possess some active compounds that have immense anti-cancer properties. The role of mushrooms in cancer treatment also complement chemotherapy and radiation therapy which have many side effects like anaemia, bone marrow suppression and nausea etc. Some examples are Phellinus linteus, Inonotus obliquus, Grifola frondosa, Agaricus blazei, Pleurotus ostreatus, Cordycep smilitaris, Lentinula edodes, Funalia trogii, Hericium erinaceus, Ganoderma lucidum and many more.16 Some of active anticancer substances possess by this mushrooms are hispolon, lectin, krestin, lentinan, illudin S, calcaelin, psilocybin, and grifolinect.16 Besides the polysaccharides, beta-glucan having ABSTRACT Objective: This study aims to quantify the anti-oxidant activity of the methanolic extract of Macrocybe crassa and its anti-proliferative activity on normal and cancer cells. Methods: The anti-oxidant potential of the extract was determined by several in vitro assay system like DPPH radical scavenging activity, superoxide anion scavenging activity, percentage inhibition of lipid peroxidation and nitric oxide (NO) scavenging activity. Anti-proliferative activity was tested by MTT assay on breast cancer cell line MCF7, Human acute T lymphoblastic leukaemic cell MOLT-4 and Peripheral Blood Mononuclear Cells or PBMC isolated from a healthy donor to check its cytotoxic effect on normal cells. Results: Results indicated that the methanolic extract of Macrocybe crassa shows appreciable anti-proliferative activity against breast cancer cell line MCF7 and negligible effect on MOLT4 cells. In contrast no significant anti-proliferative effect has been observed in normal PMMCs. Moderate anti-oxidant activity was recorded in methanolic extract. Conclusion: Methanolic extract of of Macrocybe crassa with moderate anti-oxidant activity and specific anti-proliferative effect on MCF7 holds a great promise can be used for isolation of bio molecules for treating Breast Cancer.