Sideritis caesarea H. Duman, Aytac & Baser of the Lamiaceae is an Anatolian endemic species, and is mainly used as herbal tea and folk medicine. This present study aimed to determine and compare the chemical compositions of the volatile components of S. caesarea specimens collected from different localities in Kayseri province, Turkey: Sariz town (samples A and B), Pmarbasi-Kaynar (sample C) and Pinarbasi-Sirvan Mountain (sample D), respectively. Initially, the essential oils of the aerial parts were obtained by hydrodistillation and analysed both by gas chromatography-flame ionization detector (GC-FID), gas chromatography/mass spectrometer (GC/MS), simultaneously. Major volatile components of samples A and D were characterized as hexadecanoic acid (19.7 and 20.5%), caryophyllene oxide (6.7 and 20.2%), beta-caryophyllene (6.5 and 12.6%), respectively. In sample B, hexadecanoic acid (14.6%),) beta-caryophyllene (11.5%) and caryophyllene oxide (8.3%) were detected as the major components. Whereas caryophyllene oxide (13.7%), hexadecanoic acid (8.5%) and spathulenol (6.1%) were the main components of the essential oil of sample C. Besides the chemical profiling, in vitro antimicrobial effects of samples were evaluated against a panel of six pathogenic microorganisms. Inhibition zones of the tested samples varied against bacteria with low to moderate activity, where no susceptibility against Candida albicans was observed.