The Composition of the essential oils from three Umbelliferae species of Iran , Tetrataenium lasiopetalum (Boiss.) Mandem ., Dorema ammoniacum D.Don., which is endemic to Iran, and Leutea petiolare (DC.) M.Pimen. obtained by hydrodistillation were analyzed by GC and GC/MS. Germacrene D (17.72%) and (E,Z) farnesol (12.58%) were the main components in the oil of aerial parts of T. lasiopetalum. The major compound in the stem oil of D. ammoniacum was α-muurolol (13.68%), whereas the leaf oil contained (E)-β-ocimene (30.94%), γ-terpinene (11.09%), p-cymene (10.03%) and (Z)-β-ocimene (7.11%). Terpinolene (13.93%, 8.28% and 10.27%) , (E)-β-ocimene (10.24%, 24.63% and 10.46%) and endo-fenchyl acetate (15.1%, 7.42% and 7.57%) were the main constituents in the leaf, fruit and stem oils of L. petiolare respectively.