10.22376/ijpbs.2019.10.1.p1-12 Volume 8 Issue 4 2017 (October - December) Cancer is most prevalent disease occurring in human beings now a days. Cancer remains the second leading cause of death in the world. In its projection, the Indian Council of Medical Research (ICMR) said in 2016 the total number of new cancer cases is expected to be around 14.5 lakh and the figure is likely to reach nearly 17.3 lakh new cases in 2020. L-Asparaginase is an anti-neoplastic agent used in the chemotherapy of acute lymphoblastic leukemia. L-Asparaginase producing marine microorganisms are isolated from coastal area of Kerala. Among 10 isolates were isolate, out of 10 isolates only one showed a potent positive result for L-Asparaginase production on screening and named as BKJM lessThan sub greaterThan 2 lessThan /sub greaterThan . Marine isolate (BKJM lessThan sub greaterThan 2 lessThan /sub greaterThan ) was tested for invitro cytotoxic activity using MTS assay against Jurkat J6(Leukemia cell line) and 3-(4, 5-dimethyl-2-thiazolyl)-2, 5- diphenyl tetrazolium bromide (MTT) on Pa lessThan sub greaterThan 1 lessThan /sub greaterThan (Ovarian cancer cell line).The IC lessThan sub greaterThan 50 lessThan /sub greaterThan (Inhibitory concentration 50) was calculated as 8.27% of the purified enzyme. L-Asparaginase inhibited the growth of both cell lines. L-Asparaginase from BKJM lessThan sub greaterThan 2 lessThan /sub greaterThan did not show any effect on normal human cells indicating that the purified enzyme have high potential for selective cytotoxicity on cancer cells. M.BHARGAVI & R. JAYA MADHURI L-Asparaginase, Cyto toxic effect, Jurkat j6 cell line, Pa1 cells and MTT Assay. 269-274