Angelica archangelica L. (Apiaceae) is one of the important perennial medicinal and aromatic plant, distributed in mid hill region of Europe and Asia. The essential oil composition of the rhizomes of Angelica archangelica from three different altitudes of Western Himalaya was investigated. Essential oils were predominantly composed of dillapiole and nothoapiole quantified by GC and identified based on their GC/MS spectra and NMR data. Composition of the essential oil varied greatly with altitude of collection as well as previous studies. Dillapiole was quantified between 35.–91.5% of the total essential oil, while nothoapiole was quantified between 0.1–62.8% of the total essential oil, which is not reported so far. Such great variations in the composition of the essential oil may be attributed to existence of chemotype and adaptation of the species to particular habitat.