Cupressus sempervirens L. (Cupressaceae) leaves, cones and young branches have been used in traditional medicine and aromatherapy. The composition of the isolates obtained by hydrodistillation from the aerial parts (plant material collected at Bainam forest, in Northwest of Alger, Algiers), were analyzed by GC and GC-MS. The leaves isolate (yield 0.22% w/w), was mainly composed of monoterpene hydrocarbons (60.8%), α-pinene (38.4%), δ-3-Carene (13.9%), α-Cedrol (10.6%), α-Terpinyl acetate (3.5%) and E-Totarol (3.0%). The cones isolate (yield 0.34% w/w) was predominantly composed of monoterpene hydrocarbons (33.I8%), with α-pinene (20.3%), δ-3-Carene (6.0%), Tepinene-4-ol (9.0%), α-Terpineol (9.0%), α-Terpinyl acetate (5.9%), α-Cedrol (9.1%), and E-Totarol (4.4%). The major components of stems isolates (yield 0.03% w/w) are rich in diterpenoids (51.9%), namely: α-pinene (5.9%), α-Cedrol (14.4%), Manool (5.6%), E-Totarol (34.7%), Ferrugenol (6.0%). Isolates were also tested against four bacteria (Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli), and two yeasts (Saccharomyces cerevisiae and Candida albicans), using the Kirby Bauer disk-diffusion method. All bacteria were susceptible to the C. sempervirens volatiles isolates. Antioxidant activity of the isolate was evaluated by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) method together with two antioxidant standards, butylated hydroxytoluene (BHA) and tert-butyl-4-hydroxy toluene (BHT). The results show antioxidant effect of all isolates less significant as BHA and BHT. Key words: Cupressus sempervirens, GC/SM, chemical composition, Antimicrobial activity, Antioxidant activity, using 1, 1-diphenyl-2-picrylhydrazyl (DPPH).