This study was carried out to investigate the growth rate, feed efficiency and carcass traits of Korean native cattle (KK), and it`s crossbreedsive Simmental carssbreed (SK), Brown Swiss crossbreed (BK) and Japanese brown crossbreed (JK) at livestock experiment station from 1979 to 1986. The effects of the mating system, year of birth and season of birth on the body weights at 6, 9, 12, 15 and 18 months of age, on the nutrient intakes at the different months of age and on the carcass traits were estimated by least squares method. Breed groups were consisted of 12 calves; of KK, 6 calves of SK, 8 calves of BK and 5 calves of JK. 1. Growth capacity The average body weights of KK, SK BK and JK were 97.1±16.4㎏, 182.8±11.5㎏, 191.8±14.0㎏ and 127.9±15.4㎏ at 6 months (P$lt;0.05), 169.0±20.9㎏, 289.4±14.7㎏, 277.7±17.8㎏ and 223.8±19.6㎏ at 9 months, 242.7±29.7㎏, 424.7±20.9㎏, 386.3±25.3㎏ and 329.4±27.9㎏ at 12 months, 343.0±31.7㎏, 527.3±22.3㎏, 495.0±27.1㎏ and 410.8±29.8㎏ at 15 months, 421.6±32.9㎏, 625.7±23.1㎏, 573.3±28.1㎏ and 497.4±31.0㎏ at 18 months of age, respectively (P$lt;0.01). The average daily gains of KK, SK, BK and JK were 0.90±0.06㎏, 1.23±.004㎏, 1.06±0.05㎏ and 1.03±0.06㎏, respectively (P$lt;0.01). 2. Feed efficiency D.M. requirements per ㎏ gain of KK, SK, BK and JK were 6.48±0.30㎏, 6.50±0.25㎏, 7.52±0.30㎏ and 6.43±0.33㎏, respectively (P$lt;0.05). The average amounts of C.P, requirement per ㎏ gain of KK, SK, BK and JK were 1.03±0.05㎏, 1.06±0.04㎏, 1.23±0.05㎏ and 1.00±0.05{{ }}㎏, respectively (P$lt;0.05). 3. Carcass traits The average carcass percentages of KK, SK, BK and JK were 60.1±1.3%, 62.2±1.0%, 61.4±1.2% and 60.6±1.2%, and the average lean meat percentages of KK, SK, BK and JK were 44.3±1.2%, 46.4±0.9%, 43.3±1.1% and 43.4±1.0%, respectively. There were no significant differences among breed groups in carcass and lean meat percentage.