The Atlas cedar is an endemic species of the African North Mountains. The goal for which this work was conducted is to determine the chemical composition and to study the antibacterial and the antifungal activity of the hydrodistilized essential oil from both the winged and wingless seeds of the High Atlas Cedrus atlantica (Morocco). The essential oil is analyzed by gas chromatography and gas chromatography mass spectrometry. The essential oil yields of winged as well as wingless seeds were respectively 2.6% and 3.6%.The main constituents of the cedar wingless seeds are the α-pinene, the manool, and the bornyl acetate; whereas, the major constituents of the cedar winged seeds are the manool and the α-pinene. The antibacterial and antifungal activities of the essential oils were tested on four bacteria, three molds and four fungi of wood rot. The fungal strains tested were revealed more sensitive to the essential oil studied than the bacterial strains.