Abstract The essential oil of Micromeria biflora Benth. has been investigated for its composition by capillary GC and GC/MS. The oil was found to contain mostly monoterpene hydrocarbons and oxygenated monoterpenes. The major constituents of the oil were neral (25.3â32.2%) and geranial (26.7â41.3%). The oil produced in the winter was found to contain higher amounts of oxygenated monoterpenes than the oil produced in the summer.