The essential oils from twenty-two different Stachys species were obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). Thirty-nine compounds, which accounted for 70.5-97.8% of the total composition of the oils, have been identified. Germacrene-D (2.9-45.3%), beta-caryophyllene (2.3-62.3%), caryophyllene oxide (trace to 7.8%), spathulenol (trace to 7.8%) and alpha-cadinene (1.4-8.5%) have been identified as the main components of the essential oils. Antimicrobial assessments of the essential oils were evaluated against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Candida albicans by disc diffusion method. Most of the essential oils showed moderate activity against the studied microorganisms. (C) 2011 Phytochemical Society of Europe. Published by Elsevier B. V. All rights reserved.