<jats:p>Seventeen daucane sesquiterpenoid esters, including a new one (4), were isolated from the root of <jats:italic>Ferula hermonis</jats:italic> Boiss. The structures of the isolated compounds were elucidated on the basis of spectroscopic evidence and correlated with known compounds. The relative stereochemistry of the new compound was determined using 2D NOESY and the most stable and the lowest energy conformation was determined using molecular modelling. The antimicrobial activity was evaluated by determination of MIC using the broth microdilution method against six bacterial strains and one fungal strain (<jats:italic>Pseudomonas aeruginosa</jats:italic> PAO1, <jats:italic>Escherichia coli</jats:italic>, <jats:italic>Bacillus subtilis</jats:italic> ATCC6633, <jats:italic>Mycobacterium bovis</jats:italic> BCG Pasteur, <jats:italic>Mycobacterium tuberculosis</jats:italic> H37Rv, <jats:italic>Staphylococcus aureus</jats:italic> ATCC6538 and <jats:italic>Candida albicans</jats:italic> SC5314). There was a significant indication that compounds 15, 16, 17 demonstrated potent activity against Gram +ve (<jats:italic>S. aureus</jats:italic>, <jats:italic>B. subtilis</jats:italic>), as well as <jats:italic>Mycobacterium</jats:italic> strains <jats:italic>M. bovi</jats:italic>s BCG and <jats:italic>M. tuberculosis</jats:italic> H37Rv. None of the isolated compounds exhibited a significant antifungal activity. In the antioxidant study using the DPPH assay method, the highest radical scavenging activity was observed for compounds 15, 16, 17. Copyright © 2011 John Wiley & Sons, Ltd.