Sarang semut (Myrmecodia pendans) or ant-nest plant is a potential medicinal plant. The water extract of this plant is wellknown to cure many kinds of disease including cancer. Phytochemicals present in this plant are suspected to be responsible for its health benefits. Water extract obtained at 100C and 30 min extraction shows the highest radical scavenging activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the highest cytotoxicity towards cervix (HeLa) and breast (MDA-MB-231) cancer cells. The water extract is fractionated using n-hexane, ethyl acetate and n-butanol. The n-butanol fraction is found to contain the highest amount of total phenolic content, DPPH scavenging and cancer cell cytotoxic activities. Identification of bioactive compounds in the n-butanol fraction is performed using high performance liquid chromatography coupled with mass spectrometry and ultraviolet detector. Forty-eight antioxidant compounds are identified in the water extract, and 37 compounds among them are reported for the first time.