The Lavandula species are economically important plants cultivated for their essential oils, used in medicine, phytotherapy, aromatherapy, landscaping, cosmetics and food industries. These essential oils are mainly constituted of mono- and sesquiterpenoid alcohols including linalool, linalyl acetate, 1,8cineole, caryophyllene and camphor. The high content of linalool and linalyl acetate and low percentage of camphor, makes the species L. angustifolia the finest and most desired producers of volatile oil for various industries. The therapeutic properties of lavender essential oils result from the biological activity of certain oil constituents.  The study aims to characterize the limonene synthase (LIMS), which is directly responsible for the biosynthesis of limonene, the borneol dehydrogenase (BDH) which generates camphor through the oxidation of borneol and linalool synthase (LINS) that produces linalool by expression as genes involved in major monoterpene biosynthesis, in four different lavender cultivars (`Provence Blue`, `Sevtopolis`, `Vera` and `Codreanca`) of the Lavandula angustifolia species by quantitative Real-Time PCR. Total RNA was isolated from leaf tissue using SV Total RNA Isolation System kit (Promega). The transcriptional activity of LIMS, BDH and LINS in leaf tissue was analyzed by absolute quantification, based on”in house” standards previously amplified using GoTaq G2 Green Master Mix (Promega) and specific primers targeting a 120– 300 bp fragment size. The quantitative RT-PCR was performed in a Rotor-Gene 6000 5 Plex HRM Real-Time PCR system (Corbett) using a GoTaq 1-Step RT-qPCR kit (Promega).