Abstract Essential oils obtained by hydrodistillation from fruits of Seseli resinosum Freyn et Sint. and Seseli tortuosum L. were analyzed by GC and GC/MS. Twenty-two compounds were characterized, representing 100.0% of the oil of S. resinosum, while 27 compounds were found, representing 98.3% of the oil of S. tortuosum. The main constituents were found to be β-pinene (37.5%), 4α-hydroxygermacra-1(10)-5-diene (21.7%), α-pinene (13.7%) for S. resinosum and (E)-sesquilavandulol (37.0%), sabinene (19.7%), α-pinene (13.5%), β-phellandrene (7.8%) for S. tortuosum. Key Word Index: Seseli resinosum Seseli tortuosum Umbelliferaeessential oil compositionβ-pinene4α-hydroxygermacra-1(10)-5-dieneα-pinene(E)-sesquilavandulolsabinene