The aim of this study was to isolate the active components from the essential oil (EO) of Satureja boissieri and to investigate the cytotoxic effects of these components on human cervical epithelioid carcinoma (HeLa) cell line. The major components of EO were found to be p-cymene (23.15%), -terpinene (22.84%), thymol (18.96%) and carvacrol (21.25%) using GC-MS. The components were separated by column chromatography and p-cymene, thymol and spathulenol were isolated as pure terpenoids. The cytotoxic activity of the components was investigated using the xCELLigence system (Real Time Cell Analyzer). The pure compounds, p-cymene and thymol exhibited excellent cytotoxic effects against HeLa cell line.