This study was carried out to investigate the effects of dietary supplementation of quercetin ($Kocetin^{TM}$, QR) on antioxidative activity and meat quality of beef cattle (Holstein-Friesian). Beef cattle were divided into 3 groups; dietary supplementation of QR at 21 (n=4) and 42 ppm (n=3), and non-supplemented control (n=4). The QR comprised of 10% of quercetin. After slaughtering the beef cattle, loins were obtained and analyzed. Dietary supplementation of QR at 42 ppm showed significantly higher final pH of loin but did not affect the water holding capacity, drip loss, cooking loss, surface color, total phenolics content, 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity. Dietary QR showed no difference in both 2-thiobarbituric acid reactive substances and volatile basic nitrogen values. Textural characteristic results also showed no difference, except for cohesiveness. Cohesiveness was significantly higher in loin from beef cattle treated by dietary QR at 42 ppm when compared to control. Results suggest that dietary QR, which has only 10% of quercetin is not sufficient to have positive biochemical effects on beef meat quality.