Abstract Ferula gummosa Boiss. (Umbelliferae family) is one of the native medicinal plants of Iran that its gum and dried latex are exported from Iran. The chemical composition of the volatile oil of gum and latex of F. gummosa collected in summer 1999 near Kashan (Isfahan Province, Center of Iran) was examined. The amount of the oil was determined after hydrodistillation and its composition was examined by GC and GC/MS. The essential oil yield was 10.6% and pale-yellowish in color. The major components of the oil were β-pinene (58.8%), δ-3-carene (12.1%), α-pinene (5.7%) and β-myrcene (4.6%).