The present study was carried out on virgin olive oil extracted from four olive cultivars namely: Chemlali, Kronaki, Frantoio and Pecual in an attempt to shed light upon physical and chemical properties of olive oils, assessment of fatty acids composition, oxidative stability of extracted oils, antioxidant activity, as well as fractionation of unsaponifiable matter by gas liquid chromatography. The main results revealed that: 1-     Chemlali fruits had the highest oil content (47.20%). Meanwhile, Pecual fruits recorded the lowest oil content (35.4%). 2-     Chemlali oil recorded low acid value (0.738%). Meanwhile, Kronaki, Frantoio and Pecual samples recorded the highest values (0.845, 0.828 and 0.860%; respectively). 3-     Iodine value of studied samples ranged from 82.5 to 86.5 for Chemlali and Kronaki cultivars; respectively. 4-     Chemlali oil recorded the highest value of peroxide value (10.98 meq/kg). Meanwhile, the lowest value was was recorded Frantoio oils (8.77 meq/kg). 5-     Kronkai oil recorded the highest percentage of unsaponifiable matter (1.84%), the lowest value was recorded for Pecual oil (1.36%). 6-     Kronaki cultivar oil recorded the highest oxidative stability (26.20 hr.), followed by Chemlali, Frantoio and Pecual (23.80, 21.60 and 19.40 hr.; respectively). 7-     Oleic acid was the most predominant unsaturated fatty acid in all studied samples, followed by linoleic acid. Meanwhile, palmitic acid was the major saturated fatty acid. 8-     The studied virgin olive oils recorded the highest value of antioxidant activity in sunflower oil in comparison with synthetic antioxidant (BHT). Sterol fraction represented about 29.60, 29.84, 29.45 and 29.05% of the total unsaponifiable matters of Chemlali, Kronaki, Frantoio and Pecual olive cultivar oils; respectively. Among the sterol components, b-sitosterol was the predominant component in all studied samples