In this research, the variations in the chemical composition of the Lavandula angustifolia Mill. essential oil, the Romanian variety Moldoveanca 4, obtained from the same culture, in the same harvesting and extraction conditions, during the years 2016-2018, representing the years 2-4 of culture. Lavandula angustifolia Mill. flowers were supplied from an ecological-crops from N-E Romania and the essential oils were obtained by hydro distillation of freshly harvested flowers. To determine the chemical composition, the essential oil was semi-quantitatively analysed by using gas chromatography coupled with mass spectrometry (GC-MS). In all the samples, 30 organic compounds were identified, linalool and linalyl acetate being in similar concentrations (23.51-27.39% for linalool and 26.60-40.66% for linalyl acetate). Changes in chemical composition were observed in 2017 and 2018. Also, in 2017 was determined an increase in the quantity of linalyl acetate (from 26.60 to 40.66 %), and a slight decrease in linalool content; in 2018, the concentration in linalyl acetate remained approximately the same as in 2017 (38.03 versus 40.66 %) and there was an increase in linalool compared to the previous years (27.39 %, compared to 23.51 % in 2017 and 26.22 % in 2016). The chemical composition of the essential oils obtained from flowers of Lavandula angustifolia L., Moldoveanca 4 variety, showed substantial changes of the chemical profile describing the compounds during the analysed three years, as was determined by GC-MS analyses.