Different extracts of aerial parts of Achillea millefolium were tested for their in-vitro antimicrobial activity. These extracts include water extract, hexane extract, chloroform extract, ethyl acetate extract (hydrolysed and non-hydrolysed) and methanolic extract. Microorganisms, tested in this study were: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Trichophyton rubrum, Trichophyton mentagrophyt.es and Trichophyton tonsurans. Chemical investigation showed that Achillea millefolium contains different active compounds such as flavonoids, tannins, saponins, glycosides, terpenes, steroids, alkaloids and coumarins. The TLC (Thin Layer Chromatography) tests for methonolic extract of Achillea millefolium plant as compared with standard showed the presence of rutin with other compounds under UV light. The in-vitro tests showed that the best extract of Achillea millefolium with highest antibacterial activity is the chloroform extract followed by the methanolic extract and ethanolic extract at different concentrations. Chloroform extract of Achillea millefolium appeared with highest activity of inhibition on the fungal growth as compared with the ethanolic and methanolic extract at different concentrations. Essential oils of Achillea millefolium achieved by hydrodistillation were highly active against bacterial growth and some fungi and less effective against fungal growth.