Intoduction: Marine resource of macroalgae Eucheuma cottonii from East Lombok, Nusa Tenggara Barat, Indonesia, have potential as anti-cervical cancer agent. Objectives: Finding cytotoxic activity of Eucheuma cottonii hexane, ethylacetate, chloroform and ethanol extracts against cervical HeLa cells by MTT cell proliferation assay. Methods: The extracts was tested in phytochemical and cytotoxic activity test. Phytochemical test to identify composition of secondary metabolite such as flavonoid, alkaloid, saponins, tannin, triterpenoid, steroid and glycoside. The amount of substances contained in the extract sample was analyzed by Thin Layer Chromatography (TLC). Cytotoxic activity using HeLa cells. Results: Phytochemical test of E. cottonii extracts showed the positive result for metabolite of flavonoid, whereas the TLC analysis revealed that the extracts containing five chemical compounds. Ethanol, n-hexane, chloroform, and ethyl acetate extracts of E. cottonii exhibited a strong cytotoxic activity against cervical HeLa cells with IC50 of 7.54 μg/mL, 5.73 μg /mL, 4.82 μg /mL and 4.34 μg / mL, respectively. Conclusion: The results suggest that macroalgae Eucheuma cottonii could be used as a new anti-cervical cancer’s candidate.