Abstract The essential oils obtained from the aerial parts of Hippomarathrum microcarpum and Physospermum cornubiense, growing in Iran, were analyzed by GC and GC/MS. Thirty-three compounds representing 95.2% of the oil of H. microcarpum, and nine compounds representing 91.5% of the oil of P.cornubiense were charactrized. The major components of the oil obtained by hydrodistillation from H.microcarpum were α-pinene (15.9%), β-caryophyllene (15.7%), β-phellandrene (7.8%) and germacrene-D (6.8%) and the major components of the oil of P. cornubiense were caryophyllene oxide (27.5%), limonene (16.2%) and β-caryophyllene (15.8%).