Metabolism trial was carried out to estimate the energy and protein requirements for Korean native heifers. Nine heifer calves weighing about 150㎏ were randomly assigned into three target daily gains (0.2㎏, T₁; 0.6㎏, T₂; 0.8㎏, T₃) with interval of BW 50㎏ through BW 350㎏, aiming to estimate the energy and protein requirements. The amount of nutrient to be fed was based on NRC requirements (1984), and the ration consisted of hay, rice straw and grass silage as roughage source, and concentrate mixture. Average daily gains across body weight classes were 0.30(T₁), 0.62(T₂) and 0.67㎏(T₃), respectively. Except for crude fiber, digestibilities and nutritive values of experimental ration were increased with the increase of daily gain. As expected, nitrogen intake was significantly(P$lt;0.05) increased with the increase of daily gain, but there were no differences in digestible nitrogen intake and nitrogen retention between T₂ and T₃ group. Based on pooled data of body weight classes, nitrogen(N) and digestible nitrogen(DN) requirements were estimated as follows; N requirement(g/W^0.75/day) = 0.98+1.25DG-0.44DG² (R²=0.42**), DN requirement(g/W^0.75/day) = 0.40+1.19DG-0.24DG² (R²=0.49**) Metabolizable energy intake, heat production and energy retention tended to increase with the increase of daily gains, not with body weight, although there was no difference between T₂ and T₃ group. Energy losses expressed as % of gross energy(GE) intake was higest from feces(42.8%), followed by heat production(42.3%), and lowest from urine(2.0%). Total digestible nutrient(TDN), DE and ME requirements were as follows; TDN requirement(g/W^0.75/day) = 28.13+60.40DG-14.03DG² (R²=0.48**), DE requirement(㎉/W^0.75/day) = 134.34+ 220.59DG-71.90DG² (R²=0.54**), ME requirement(㎉/W^0.75/day) = 116.98+171.32DG-35.73DG²(R²=0.54**). Total digestible nutrient, DE and ME requirements for maintenance were 28.13g, 134.3㎉ and 116.98 ㎉/W^0.75/day, respectively. The estimated NEm requirement from the relationship between ME intake and heat production was 76.5㎉/W^0.75/day.