Increasing antibiotic resistance in strains of bacterial pathogens increase the attitude of people to find new compounds as an appropriate alternative to antibiotics. In this study, the antimicrobial effects of methanolic extract of Mentha pulegium against S. aureus and E. coli strains were investigated. After collecting the plants, essential oil of aerial parts of the plant was done by distillation with water through the clevenger apparatus. Gas chromatography-mass spectrometry (GC / MS) was used to identify the chemical composition of the essential oil. M. pulegium extract was prepared by soxhlet extractor method and their antimicrobial effects were investigated using agar well diffusion and dilution methods. The results of GC / MS analysis showed 22 compounds in M. pulegium plant. The results showed that M. pulegium methanolic extract prevents the growth of S. aureus and E. coli bacteria. Also, S. aureus showed a higher sensitivity to different concentrations of M. pulegium extract. Therefore, after supplementary studies, it could be used as a substitute the treatment of infections.