Abstract The water-distilled essential oils from aerial parts of Phlomis persica Boiss. and Phlomis olivieri Benth., which are endemic to Iran, were analyzed by GC and GC/MS. The oil of P. persica was found to contain germacrene D (38.2%), bicyclogermacrene (16.3%) and Î±-pinene (13.3%) as major constituents. The oil of P. oliveri was characterized also by higher amount of germacrene D (26.4%) and bicyclogermacrene (12.7%). Both oils consisted mainly of sesquiterpene hydrocarbons.