Aerial parts of Satureja hortensis (1 and 2), Satureja macrantha, Satureja cuneifolia, Satureja thymbra and Satureja aintabensis collected from different parts of Turkey were subjected to hydrodistillation to yield essential oils and analysed by GC and GC-MS. The antibacterial and antifungal activity of six essential oils and their major constituents in the gaseous state was evaluated against Escherichia coli ATCC 25292, Staphylococcus aureus ATCC 6538, Pseudomonas aeruginosa ATCC 27853, Enterobacter aerogenes NRRL 3567, Candida albicans (OGU), Penicillium clavigerum (BUB. Czp. 181), Mucor hiemalis (BUB. Malt. 163) and Absidia glauca ATCC 22752. All tested microorganisms were inhibited by the essential oils of S. hortensis 1 and 2, S. macrantha, S. cuneifolia, S. thymbra and S. aintabensis. Carvacrol was the main component in the oils of S. macrantha, S. cuneifolia and S. thymbra, respectively (64.4%, 48.7%, 39.0%). The oil of S. hortensis (2) contained (43.4%) thymol and the oils of S. hortensis (1) 40.6% thymol; S. aintabensis contained 59.0% p-cymene as the main constituent. Copyright (c) 2005 John Wiley & Sons, Ltd.