Abstract The composition of the essential oils of Achillea crithmifolia and Achillea nobilis was analyzed by GC and GC/MS. The main compounds of the A. crithmifolia essential oil were camphor (27.6%), 1,8-cineole (26.5%) and trans-chrysanthenyl acetate (18.8%), while the most abundant compounds in the A. nobilis oil were Î±-thujone (25.7%), artemisia ketone (14.8%), borneol (9.9%) and camphor (8.2%). The antibacterial activity of oils was tested for the first time. Both examined oils showed very strong antibacterial activity against all tested microorganisms (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus).