Aims:The present study examines the chemical composition of essential oil of Ruta graveleons and antioxidant activity of petroleum ether and methanol extracts of dry leaves of R. graveleons which belongs to Rutaceae family found in many parts of the India. There are few reports are available for its essential oil in India.Materials and methods:The fresh leaves were hydrodistilled by Clevenger type apparatus, the obtained essential oil was analyzed using GC-MS. The petroleum ether and methanol extracts were tested for antioxidant activity by DPPH˙ and ABTS methods.Results:The GC-MS results showed that 2-nonanol (34.25), 2-nonanone (32.15) and nonyl ester (15.43) are the major components and some of the other minor compounds are 2-dodecanone (2.77), tri decanone (2.54) and tumeronol (2.16). The preliminary phytochemical investigation of petroleum ether and methanol extracts showed the presence of carbohydrates, phenolic compounds, flavonoids, furano coumarins, fatty acids and alkaloids. So an attempt was made to find the possible sources for future novel antioxidants in food and pharmaceutical formulations.Conclusions: GC-MS studies indicated that 2-nonanone (32.15) and nonyl ester (15.43) are the major components. The methanol extract showed highest IC50 values for DPPH (19.50±1.25 μg/ml) and ABTS (48.32±0.9 μg/ml) and petroleum ether extract showed moderate activity, both results are comparable with standard employed for each method.Keywords: Ruta graveolens, Rutaceae, Gas chromatography-mass spectrometry, Essential oil, antioxidant, 2,2-diphenyl-1-picrylhydrazyl, 2,2’-azinobis( 3-ethylbenzothiazoline-6-sulphonic acid).