The essential oil of Thymus tosevii Velen. (Lamiaceae) growing wild in Greece was investigated by means of GLC, GC-MS, and the physico-chemical constants were determined. The essential oil content was 0.9%. As main constituents resulted linalool 35.5% and geraniol 27.5%. In addition twelve monoterpene hydrocarbons, nine oxygen containing compounds, one sesquiterpene, and two terpene esters were identified, making up about 98% of the oil.