Adjustment factors for adjusting the birth and weaning weights of Hanwoo were estimated using the animal model on the basis of 6,548 records on birth weight and 6,514 records on weaning weight of Hanwoo raised at Hanwoo Improvement Center, National Livestock Cooperatives Federation from 1990 to 1998. Additive adjustment factors for the age of dam estimated for birth weight were 1.6927㎏ for 2yrs, 0.5669㎏ for 3yrs, 0.5216㎏ for 4yrs, 0.0㎏ for 5-9yrs, 0.0078㎏ for 10-11yrs and 0.1861㎏ for 12yrs and older, and multiplicative adjustment factors were 1.0807, 1.0256, 1.0235, 1.00, 1.0003 and 1.0083, respectively. Additive factors for adjusting the birth weight of female to male basis was 1.5845㎏, and the multiplicative adjustment factor for female was 1.0751. Additive adjustment factors for the age of dam estimated for weaning weight were 16.1 ㎏ for 2yrs, 7.4㎏ for 3yrs, 4.7㎏ for 4yrs, 0.0㎏ for 5-9yrs, 1.5㎏ for 10-11yrs and 3.4㎏ for 12yrs and older in males, and 12.8㎏ , 7.5㎏ , 3.4㎏ , 0.0㎏ , 1.0㎏ and 2.3㎏, respectively, in females.