Secondary metabolites (flavonoids and phenolics) in the methanolic extracts of Brassica napus genotypes, spring and winter canola were evaluated. Antioxidant activity of the extracts was evaluated by β-carotene linoleic acid model system, scavenging ability of hydrogen peroxide (H2O2) assay and cupric reducing antioxidant capacity (CUPRAC) assay. Also, total flavonoid contents of the extracts were determined by aluminum chelating method. Results showed that naringin and eriodictyol were found to be in both species. Data showed that winter canola exihibited high antioxidant capacity with 60.6±0.4% in β-carotene linoleic acid model system and also CUPRAC value (4.18±0.11mM TEAC/g) and scavenging ability of H2O2 (57.12±1.13%) was higher than spring canola. However, total flavonoid content of spring canola was higher than that of winter canola. Both canola species may be of importance in variety improvement, nutraceuticals, bio-pharmaceuticals and food additives as natural antioxidants. © 2011 Wiley Periodicals, Inc..