This study aims to estimate the genetic parameters for carcass traits on Hanwoo of breeding farmhouses using Animal Products Grading Service's data of 428,812 cattle from 101 slaughterhouses nationwide from 2000 to 2005. Using carcass traits of carcass weight, eye muscle area, backfat thickness, marbling score, meat color and fat color that greatly influence Hanwoo's grade, the effects of carcass year, carcass season, sex and carcass region were estimated.Based upon carcass traits of carcass weight, eye muscle area, backfat thickness, marbling score and meat color that greatly influence Hanwoo's grade, the heritabilities and genetic parameters were estimated of 17,578 Hanwoo slaughtered in 2005 with existing herdbook, where EM-REML algorithm was used in estimating genetic parameters.The mean and standard deviation of each carcass trait are 321.42±53.62 kg, 76.25±10.43cm 2 , 9.96± 4.14mm, 3.75±2.00, 4.83±0.48 and 2.99±0.40, for carcass weight, eye muscle area, backfat thickness, marbling score, meat color and fat color, respectively. As a result of analysis on the effects of carcass year, the carcass weight, backfat thickness and meat color came out highest as 359.40±0.181, 9.82±0.017 and 4.90±0.002, respectively in 2004. As a result of analysis on the effects of carcass season, the carcass weight and eye muscle area came out highest as 345.88±0.144 and 79.57±0.033 respectively in spring, and the backfat thickness was highest as 8.78±0.013 in winter, and the meat color and fat color slightly came out higher as 4.88±0.002 and 2.96±0.001 in fall, while the marbling score was highest as 3.29±0.006 in summer. The results of the analysis on the effects of sex indicated that the backfat thickness and fat color were highest as 10.53±0.010 and 3.07±0.001 in cow, the carcass weight came out highest in Hanwoo steer as 368.03±0.068 kg, the eye muscle area were highest as 82.96±0.042 in bull, and the marbling score was highest as 4.19±0.007 in steer, and the meat color was highest as 4.89±0.001 in cow.Regarding the results of analysis on the effects of carcass region, the carcass weight, eye muscle area,

This study was carried out to investigate the correlation of body measurement type and carcass traits. This study used body measurement type and carcass traits on 1,312 heads of Hanwoo steers tested (24 months) which was from 1997 to 2002 at Hanwoo Improvement Main Center National Agricultural Cooperatives Federation. Body measurement type used the age of 18 months body measurement type, and carcass traits used the results of decision grade of Animal Products Grading Service.Observing the phenotypic correlation between carcass traits and body measurement type from the result, the weight, withers height, and chest width at age of 18 months and carcass weight showed readings of 0.690, 0.483, and 0.506, respectively. Also, eye muscle area and age of 18 months weight and chest width read 0.356 and 0.279, respectively. According to results, that improvements in weight, withers height, and chest width are likely to enlarge the eye muscle area and meat production level. Not only quality improvement but also quantity augmentation affect income and sales of the farmers. As can be seen in this study, improvements of weight, withers height and chest width should always be put to much effort while other body measurement type should be considered continuously too. In order to attain clearer results further studies should be done on body measurement type, which will contribute to the improvements of body measurement type in Hanwoo.