Abstract The chemical composition of the essential oils in 11 populations of Thymus daenensis subsp. daenensis Cleak was evaluated using GC and GC/MS. Carvacrol, thymol and geraniol were found as the main constituents in the oils of the tested populations. Variation of the oils in populations was subjected to cluster analysis and three different chemotypes including carvacrol (47.3â80.1%), thymol (53.1â72.2%) and geraniol (65.6â75.7%) were identiified. Other important components were Î²-caryophyllene (1.7â9%), p-cymene (0.1â10.9%) and Î³-terpinene (0.1â7.8%). Although Thymus is known as having high thymol content in its oil, it is revealed that T. daenensis subsp. daenensis has also a high potential for carvacrol and geraniol constituents in the oil.