Abstract The chemical composition of a hydrodistilled oil of Seseli tortuosum L. ssp. Kiabii Akhani. growing wild in Iran was examined by GC/MS. Thirty compounds, mainly monoterpenes, representing 93.6% of the oil, were identified, with Î±-pinene (21.2%), Î²-phellandrene (14.9%), Î²-pinene (14.2%) and sabinene (13.4%) as main constituents.