Ferulago species have been utilized since ancient times as antihelmentic, digestive, sedative and aphrodisiac, along with in salads or as a seasoning in view of their special odours. F. pachyloba (Fenzl) Boiss., F. trachycarpa Boiss. and F. bracteata Boiss. & Hausskn. species were investigated for their chemical compositions of essential oils and their antimicrobial activities. Antimicrobial activities of essential oils were performed via microbroth-dilution and TLC bioautography methods. GC and GC/MS were utilized to analyse the essential oils. Primary components of aerial parts, flowers, roots and fruits of F. pachyloba were found as, sabinene (16.0 %), (Z)-beta-ocimene (15.1 %); sabinene (25.8 %), (Z)-beta-ocimene (27.5 %); (E)-2-decenal (14.3 %); bicyclogermacrene (11.1 %), respectively. Primary components of aerial parts, roots and fruits of F. trachycarpa were found as, (Z)-beta-ocimene (13.8 %), spathulenol (25.0 %); (E)-2-decenal (11.9 %); spathulenol (32.8 %), bicyclogermacrene (23.0 %). Primary components of aerial parts, flowers and roots of F. bracteata were found as, 7-methoxy-6-(3-methyl-2-butenyl)-coumarin (86.7 %); beta-pinene (12.1 %), beta-phellandrene (22.8 %); (E)-2- decenal (13.9 %), hexadecanoic acid (40.4 %). Essential oils were particularly more effective against Staphylococcus aureus, with MIC values of between 0.39 and 6.25 g/mL, respectively. They did not give significant inhibition against Pseudomonas aeruginosa by TLC bioautography assay. In contrast, they had active components against S. aureus and showed significant inhibition. The antimicrobial activities against these microorganisms from these species may be attributed to the presence of the main components in the essential oils.