Korean organic Hanwoo was compared to imported beefs from the America and Australia on the quality characteristics and antioxidant activities. Crude lipid content was significantly higher in Hanwoo. Marbling of Hanwoo has been recognized as well among the comparison groups. Cooking loss of Hanwoo was significantly lower than imported beefs, and its water holding capacity was significantly higher. After cooking, share force was significantly lower in Hanwoo than imported beefs. Contents of total composition amino acid were lower in Hanwoo than imported beefs, but ratio of essential amino acid was higher in Hanwoo. In Hanwoo, contents of saturated fatty acid(SFA) were lower, and poly unsaturated fatty acid(PUFA) content was significantly higher than imported beefs. Especially, oleic acid content was ranged 53.95~ 56.05% in all tested beef samples, and its content was the highest in Hanwoo. Hanwoo was higher than imported beefs in MUFA/SFA ratio, but it was lower in PUFA/SFA ratio. Lipid peroxide content was significantly lower in Hanwoo than imported beefs during their storage for 21 days at 4°C. Contents of total phenolic and flavonoid were not significantly different among the comparison groups. Activities of DPPH and ABTS radical scavenging in Hanwoo was significantly higher than American beef, but not significantly different from Australian beef. Therefore, the quality and antioxidant activity of Hanwoo beef are thought to be more dependent on the MUFA than phenolic compounds.