BACKGROUND: Reducing the detrimental effects of free radicals, in biological and food systems by antioxidants, is important, thus providing antioxidants is necessary issue in community health and food safety. Objectives: The aim of the present study was to determine antioxidant properties of the essential oil and various extracts obtained from summer savory. Methods: Summer savory were extracted using different type solvents and chemical composition of hydro-distilled volatile oil from the aerial part of the plant and analyzed by GC/MS. the antioxidant activities were measured by 2, 2'- diphenyl-1-picrylhydrazyl (DPPH°) free radical scavenging and b-carotene-linoleic acid assays. Results: 32 compounds, which representing 98/92% of the essential oil, were detected as major components: (thymol, carvacrol and terpinene, respectively). While IC50 for DPPH radical-scavenging activity were 38.46± 0.12, 37.73 ±0.17, 30.76±0.63 µg/mL for water, methanol, and ethanol extracts, respectively, it was 96.15±0.13 µg/ml for essential Oil. 80.3, 76.25, 74.3 and, 52.46 % inhibition were shown for water, ethanol, methanol extracts and essential oil in b-carotene/linoleic acid assay, respectively. These parameters for BHT were 4.9±1.9 µg/mL and 88.88% for DPPH and b-carotene-linoleic acid tests, respectively. According to the results in this study, all treatments comparing with control ,displayed strong antioxidant and radical_scavenging properties. The highest radical scavenging effect was observed in ethanol extract.The aqueous extract exhibited the greatest inhibition compared with others. Meanwhile, in both assays the extracts had more antioxidant activity than the essential oil (p<0.05). Conclusions: It seems the extracts (aqueous and alcoholic) and essential oil, could be considered as a cheap, easily accessible and potential source of natural antioxidants for food and pharmaceutical purposes.