¹Namik Kemal University , Art and Science Faculty, Department of Chemistry, Tekirdağ - TURKEY DOI : 10.12991/mpj.20151910462 The antioxidant activities of the extracts prepared from Brassica napus"s seeds (canola seeds) was determined in this study. Brassica napus"s seeds were collected from eight different regions of Turkey. Extraction experiments were carried out with 100% hexane, 100% acetone, 100% methanol, 100% ethanol, %75 hexane-water, %75 acetone-water , 75% methanol-water, 75% ethanol-water, %50 hexane-water, 50% acetone-water, 50% methanol-water, 50% ethanol-water at 25 °C overnight and were mixed by magnetic stirrer during 1h, 2h, 4h, 8h to determine optimal extraction conditions. According to the results of UV/VIS spectra, 100% hexane extraction managed at 25 °C overnight was chosen for working with ABTS/Persulphate, N,N-dimethyl-p-phenylenediamine (DMPD) and CUPRAC methods. CUPRAC and ABTS/Persulphate methods"s total antioxidant capacity (TAC) were calculated as Trolox equivalent. In DMPD method, antioxidant capacity of the extracts was determined by inhibition of DMPD radical cation. DMPD method analysis results of Brassica napus"s seeds showed the greatest effectiveness, with inhibition values of 2.00 ± 0.07% and 17.1± 0.03%. The antioxidant activities of Brassica napus"s seeds ranged from 0.29±0.04 mol/g and 0.48±0.01 mol/g for CUPRAC method and 0.36 ± 0.01 mol/g and 0.55± 0.05 mol/g for ABTS/Persulphate method. Keywords : Antioxidant activity, Brassica napus"s seed, ABTS/ Persulphate, CUPRAC, DMPD Methods, Trolox