The essential oils isolated by hydrodistillation from freshly obtained aerial parts of sea fennel (Crithmum maritimum L.) were found to be a yellow liquid, obtained in a yield of 0.2% (vol/wt) based on wet weight. The essential oils obtained from young leaves and branches of C. maritimum, collected at two different locations in Turkey (Sipahili and Yesilovacik), were analyzed by gas chromatography-mass spectrometry. Twenty-three components were identified accounting for more than 99% of the total oils. The oils contained mainly monoterpenes, amounting to 89.0% and 99.6%, respectively, of the oils, with gamma-terpinene (36% and 32%), beta-phellandrene (21% and 22%), and sabinene (13% and 9%) as the main components.