Abstract The essential oil of Thymus richardii Pers. subsp. nitidus (Guss.) Jalas which is a relict endemic of Marettimo Island (western Sicily-Italy), has been analyzed for the first time by GC, GC/MS. Thirty-six compounds were identified, among which Î²-bisabolene (32.3%), carvacrol (13.1%), methyl thymol (12.4%), trans-dihydrocarvone (5.1%), T-cadinol (4%) and Î²-caryophyllene (3.4%) were the main constituents. This is the first thymus species containing Î²-bisabolene as principal constituent