Microwave hydrodiffusion and gravity (MHG) is a novel technique that allowed microwave heating of plant material without addition of any solvent/water combined with earth gravity effect to drop the extract out of the system. It is a green, rapid and powerful technology that has been used to extract essential oil. The aim of this study was to extract essential oil from rosemary using MHG and the chemical composition and antioxidant capacity were compared with oils obtained with conventional hydrodistillation. The extraction was performed using microwave oven (NEOS-GR, Milestone) with 100 g of sample at 400 W for 20 min. For hydrodistillation was used 100 g and 500 mL of water, and the extraction was performed for 180 min in a Clevenger apparatus. Chemical composition was evaluated by a GC-FID and a fused silica capillary column RTX-5MS (30m × 0.25mm × 0.25 µm) and a GC/MS was used for compounds identification. Antioxidant capacity was analyzed using ORAC method. MHG extraction presented similar yield compared to hydrodistillation with 4.75% by HD and 4.52% by MHG. In both methods the same compounds were identified but with changes in the quantity, represented by 14 compounds, being 8 hydrocarbons and 6 oxygenated compounds. The results showed with MHG extraction increased the amount of the major compounds, 1,8-cineol (52.2% in MHG and 49,9 in HD) and camphor (17,9% in MHG and 16,0% in HD). Essential oils extracted with MHG also presented higher total amount of oxygenated compounds (79.8% compared to 74.5% by HD). In addition, antioxidant capacity was higher from rosemary essential oil obtained by MHG with value of 354.8 instead of 281.2 µmol trolox/g oil with HD. MHG provided essential oil extraction faster with a better chemical composition and antioxidant activity.