Abstract The essential oils of seven species of oregano (Origanum vulgare L. ssp. gracile (Koch), Origanum acutidens (Hand.-Mazz.) Ietswaart, Origanum hypericifolium O. Schwarz et P.H. Davis, Origanum bargyli Mouterde, Origanum saccatum P.H. Davis, Origanum solymicum P.H. Davis, and Origanum leptocladum Boiss.) were studied by GC and GC/MS. Eighty-five constituents were identified. The discriminant components of these oils were p-cymene, Î³-terpinene, cis- and trans-sabinene hydrate, borneol, terpinen-4-ol, Î±-terpineol, thymol, and carvacrol. Some of the species were similar to those described in the literature, and new chemotypes are reported.