The essential oil analysis of Mentha piperita L. (Peppermint) has been done for the first time from study area of Northern Indian region of Kullu (1362m) district of Himachal Pradesh. The extraction yield for the essential oil of M. piperita L. was 0.42% for sample M-7. The oil was analyzed by GC-MS, the components of oil were identified by comparing their retention indices and mass spectra fragmentation patterns with those stored on the MS-computer library and also from the published literatures. The major constituents reported from essential oils of M. piperita were: L-Menthone (28.66%); Menthol (9.94%); Piperitone oxide (16.0%); Eucalyptol (7.03%); L-Menthone (3.13%); Isoneomenthol (2.93%); á-Phellandrene (3.21%); ä-3-Carene (3.27%); dl-Limonene (2.53%); á-Pinene (2.02%), etc. Furthermore, anti-microbial activity of oil was evaluated using agar well diffusion method. The anti-microbial test results showed that the oil had a potential anti-microbial activity against all seven Gram+ve and Gram-ve bacterial strains such as: Pseudomonas fluorescence, Salmonella typhimurium, Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Staphylococcus epidermis and Acenetobactor calcoaceticus. Essential oil showed maximum zone of inhibition and minimal inhibition concentration against Bacillus subtilis (MTCC-2451) and Pseudomonas fluorescence (MTCC-664) bacterial strains.