Artemisia sieberi Besser (Asteraceae) is locally known as âdermanehâ in Iran. It is traditionally used for treatment of different ailments. Thirteen samples of A. sieberi essential oils from Iran and France were analyzed by gas chromatographyâflame ionization detector (GCâFID) and GCâmass spectrometry (GCâMS). The antimicrobial activities of A. sieberi oils and their main components were evaluated against some food pathogens by disc diffusion and microbroth dilution assays. Their antioxidant activities were also evaluated by 1,1-diphenyl-2-picrylhydrazyl assay. The results of chemical composition analysis of A. sieberi essential oils showed the presence of Î²-thujone (0â11.6%), camphor (2.8-42.9%), 1,8-cineole (0.0-48.7%) and Î±-thujone (0-62.1%). The results of antimicrobial evaluations showed that all essential oils had the same antimicrobial activity and the most sensitive microorganisms to A. sieberi oils were Staphylococcus aureus and Candida albicans, followed by Pseudomonas aeruginosa and Escherichia coli. Aspergillus niger was the most resistant one to A. sieberi oils. The antimicrobial activities of Î±-thujone, camphor and 1,8-cineole were stronger than that of A. sieberi oils. There was a significant difference among the antioxidant activities of essential oils. The antioxidant activity of 1,8-cineole was higher than the other main components.