Cagaiteira, the fruit popularly known as cagaite, belongs to the Myrtaceae family. Seed oil cagaite (Eugenia dysenterica DC) was obtained by three methods of extraction, extraction using an ultrasound (OCU), extraction by mechanical pressing (OCP) and extraction with Soxhlet extractor (OCS) in 3 different times (3, 6 and 9 h) and the content of fatty acids and physicalchemical properties were compared. The rate of saturated fatty acids ranged from 19.46% (OCP03) to 31.18% (OCS09), while the amount of unsaturated fatty acids ranged from 54.72% (OCP03) to 67.64% (OCS09). Linoleic and linolenic acids, important in nutrition food, varied between 32.22-38.11 and 5.55-8.78%, respectively. For oxidative stability, OCUAq (heated ultrasound extraction) samples showed the highest induction periods, showing a positive correlation with antioxidant activity and phenol content, demonstrating the efficiency of the use of ultrasonic extraction to obtain quality oils from cagaite seeds.