This study was conducted to evaluate the effects of dietary supplementation of catechins and wheat bran on growth performance, carcass characteristics and meat color using forty-eight Hanwoo steers. Each steer was randomly assigned to one of four treatments. Treatments were as follows: control, catechins, wheat bran, and catechins+wheat bran (CW). At the end of the feeding trial, blood samples were collected for analysis of hemoglobin and iron concentration, and then steers were slaughtered at a commercial abattoir. Catechins, wheat bran, and CW had no effect on growth performance and carcass characteristics. Percentage of myoglobin in M. longissimus dorsi was not affected by treatments. Percentage of oxymyoglobin was increased (p<0.05) by CW and maintained at the highest level (p<0.05) for CW during meat display time up to 24 h. Percentage of metmyoglobin was the lowest (p<0.05) for CW between 5 and 24 h during display time. Although blood iron concentration was not affected by treatments, total concentration of muscle iron was the lowest (p<0.05) for CW compared with that of other treatments. Therefore, the results of the present study suggest that CW may provide good protection against oxidation of myoglobin, and might be an effective dietary supplement for improving meat color in the late fattening period of Hanwoo steers.