essential oils isolated from the branchlets of two populations of cupressus arizonica greene (cupressaceae) growing in uttarakhand himalaya (india) were analyzed by gc and gc/ms in order to determine the variation in composition of their constituents. a total of 36 constituents representing 90.7-92.2% of the total composition have been identified in two locations. in the oils, monoterpenoids (90.0-90.7%) were the principal class of the components (oxygenated monoterpenes, 46.3-52.6%; monoterpene hydrocarbons, 37.4-44.4%), while sesquiterpene hydrocarbons found in lesser amounts (0.7-1.5%). umbellulone was identified as the major constituent of the essential oils, which ranged from 20.9 to 30.6%. the other main constituents in the essential oils were found to be limonene (8.0-12.9%), -pinene (7.1-8.1%), sabinene (6.6-7.0%), p-cymene (3.2-5.9%) and terpinen-4-ol (4.2-5.6%). in summary, the characteristic of c. arizonica essential oil from uttarakhand himalaya (india) is due to the presence of umbellulone and limonene in higher amounts.