Abstract The essential oil of the dried flowering aerial parts of Lallemantiaiberica Fisch. et C.A. Mey. (Labiatae), collected from the suburb of Larijan, north of Iran, in July 2003, was isolated by hydrodistillation and analyzed by means of GC and GC/MS. Among the 26 components identified in this oil, p-cymene (22.1%), isophytol (19.8%), T-cadinol (11.1%), 3-octanol (8.1%), caryophyllene oxide (7.4%) and terpinen-4-ol (5.7%) were the major constituents. Key Word Index: Lallemantia iberica Labiataeessential oil compositionp-cymeneisophytolT-cadinol