Chemical composition and antimicrobial effects of essential oils derived from Salvia mirzayanii were determined using GC and GC/MS. In this research four habitats in Larestan region were determined (A-D).The results showed that ecological factors had significant effect on oil yields of S. mirzayanii. The components were various in different regions. Linalyl acetate (18.64%), 5-neo-cedranol (17.43%), a-Terpinyl acetate (10.81%), 7-epi-a-selinene (9.18%), Bicyclogermacrene (5.33), Linalool (4.77%), 1,8-Cineol (4.53%) were the main components. The antimicrobial activity of essential oil of S. mirzayanii was studied against three bacteria (Shigella dysenteriae, Staphylococcus aureus and Escherichia coli). Antimicrobial activities according to the disk diffusion method and MIC values were performed and showed that essential oils of S. mirzayanii revealed antimicrobial activity against bacteria in all regions. In all microorganisms MIC value was 0.625 μl/ml and inhibition zones ranged from 8 to 17.67 mm. The maximum and minimum antimicrobial activity was observed on Staphylococcus aureus and Escherichia coli, respectively.