Abstract Chemical composition, and antioxidant and antimicrobial activities of the essential oil isolated from aerial parts of Mentha spicata L. (spearmint) were investigated. The oil content was found to be 1.2%. A total of 19 chemical constituents were identified in the spearmint oil using GC and GC/MS. The main components were carvone (51.7%) and cis-carveol (24.3%), followed by limonene (5.3%), 1,8 cineol (4.0%), cis-dihydrocarvone (2.2%), carvyl acetate (2.1%) and cis-sabinene hydrate (1.0%). The investigated oil exhibited good antioxidant activity as assessed by DPPH free radical-scavenging ability, bleaching Î²-carotene in linoleic acid system, and inhibition of linoleic acid oxidation. Antimicrobial activity of spearmint oil and its major components (cis-carveol and carvone) was followed by disc diffusion and minimum inhibitory concentration (MIC) assays against four strains of bacteria: Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Pasturella multocida and five pathogenic fungi: Aspergillus niger, Mucor mucedo, Fusarium solani, Botryodiplodia theobromae, and Rhizopus solani. All the tested microorganisms were strongly affected indicating an appreciable antimicrobial potential of spearmint oil.