Apart from being a popular spice, Origanum species is very important taxa as an herbal medicine for their several pharmacological activities. Essential oils of Origanum species bearing phenolic monoterpenoids such as carvacrol and thymol demonstrated strong antimicrobial properties. In the present study hydrodistilled essential oil of endemic species Origanum boissieri Ietswaart were analysed by GC and GC/MS techniques simultaneously. Thirty compounds representing 95.1 % of the total oil were identified. Carvacrol (39%) and p-cymene (32%) were detected as the main components of the oil. Total methanol extract and essential oil of the flowering aerial parts of the plant with the carvacrol and p-cymene were screened for its antibacterial and anticandidal properties by using microdilution broth assay. Bacillus cereus, Bacillus suhtilis, Staphylococcus aureus, Staphlylococcus epiderrnidis and Listeria inortocytogenes were strongly inhibited by the oil between the concentrations of 15,6 - 62.5 mu g/mL. O. boissieri extract and the oil showed moderate effects against all tested Candida strains having MIC values of 125-1000 mu g/mL.