Abstract Water-distilled essential oils from aerial parts of Thymus atticus and Thymus roegneri were analyzed by GC/MS. Sixty four compounds in the oil of T. atticus and thirty eight compounds in the oil of T. roegneri were identified representing 97.77% and 98.84% of the total components detected, respectively, with thymol (37.15% and 58.23%), Î²-cymene (9.00% and 12.94%) and carvacrol (7.76% and 8.59%) as respective major constituents. Key Word Index: Thymus atticus Thymus roegneri Labiataeessential oil compositionthymolp-cymenecarvacrol