Seed oils of Origanum onites L. from the Antalya and Mugla regions and O. vulgare L. from the Kirklareli region of Turkey were extracted with hexane in a Soxhlet apparatus. The oil yields were 14.1-20.0 and 18.5%, respectively. FA compositions of the seed oils were determined by GC and GC/MS. Twenty FA were identified in both O. onites and O. vulgare seeds. The major FA of both species were linolenic (56.3-57.0%; 61.8%), linoleic (21.5-21.7%; 18.8%), oleic (8.7-8.9%; 5.9%), palmitic (5.9-6.5%; 5.5%), stearic (2.1-2.4%; 2.1%), and (Z)-11-octadecenoic (0.6-0.8%; 0.5%), respectively.