In nature, essential oils play an important role in the protection of the plants by exerting anti-bacterial, -viral, -fungal, -oxidative, -genotoxic, and free radical scavenging properties, as well as in some cases acting as insecticides. Several Satureja species are used in traditional medicine due to recognized therapeutic properties, namely anti-microbial and cytotoxic activities. The purpose of the present work was to determine the biologic activity of the essential oil of S. khuzistanica Jamzad (Lamiaceae) against four human cancer cell lines, as well as its inhibitory effects against a wide array (i.e. n = 11) of pathogenic bacteria and fungi. The essential oil was isolated by hydro-distillation and analyzed by GC-FID and GC-MS. Carvacrol (92.87%) and limonene (1.2%) were found to be the main components of the isolated oil. Anti-microbial activity of the essential oil was assessed using a disc diffusion method; an MTT cytotoxicity assay was employed to test effects of the oil on each cancer cell line. The oil exhibited considerable anti-microbial activity against the majority of the tested bacteria and fungi. The test oil also significantly reduced cell viability of Vero, SW480, MCF7, and JET 3 cells in a dose-dependent manner, with the IC50 values calculated for each cell type being, respectively, 31.2, 62.5, 125, and 125 μg/ml. Based on the findings, it is concluded that the essential oil of S. khuzistanica and its major constituents have a potential for further use in anti-bacterial and anti-cancer applications, pending far more extensive testing of toxicities in normal (i.e. primary) cells.