The experiment was conducted in the years 2004-2005. The aim of the study was to determine the chemical composition of essential oils from garden thyme herb in the first year of cultivation. Essential oil was achieved in distillation with water vapor according to Polish Pharmacopoeia VI. Qualitative and quantitative composition of essential oils was analyzed using gas chromatography combined with mass spectroscopy technique (GC/MS). The analysis revealed the presence of 37 chemicals in essential oil made of thyme, including one unidentified. Thymol, a-terpinene, p-cymene and carvacrol were the main components of essential oil achieved from garden thyme cultivated in southeastern Poland.