The genus Nepeta, belonging to the Lamiaceae family, has 67 species in Iran, most of which are endemic. In this study we provide a qualitative and quantitative comparison of essential oil of leaves, flowers, stems and roots. Nepeta bornmuelleri Hausskn. ex Bornm., an endemic and aromatic species, was collected from Hezar mountain, Kerman province, Iran, in May 2011. The essential oils of leaves, flowers, stems and roots of the plant were separately extracted using hydrodistillation method and analyzed by GC and GC/MS. In the leaf and flower oils, 38 and 19 components were identified, representing 98.% and 94.5% of the total oils, with 4ab, 7a, 7ab-nepetalactone (29.2% and 26.8%), 1, 8-cineole (19.6% and 14.6%), 4aa, 7a, 7aa-nepetalactone (6.6% and 19.5%) and b-pinene (18.9% and 11.4%) as the main constituents, respectively. The stem oil was characterized by higher amount of 4ab, 7a, 7ab-nepetalactone (39.8%), caryophyllene oxide (24.1%) and 1,8-cineole (12.8%) among the 9 components comprising 95.8% of the total oil. Furthermore, 12 compounds were identified in the root oil, representing 99.3% of the total oil.4ab, 7a, 7ab-Nepetalactone (73.2%) and 4aa, 7a, 7aa-nepetalactone (13.4%) isomers were found to be the major constituents. As a result, nepetalactone was the dominant component in the essential oils of N. bornmuelleri.