This study was carried out to investigate growth performance, energy and protein metabolism of breast and formula fed infants from birth to 3 months postpartum. There were four groups : breast fed(BF) and three formula fed groups(FFM, FFN and FFP). There was no significant difference in the height of infants according to feeding method and formula brands. However, mean weight of FFM was significantly higher than that of FFP and BF at 1 and 3 months postpartum, respectively. Mean head circumference of FFN was lowest among groups. The average intake of breast milk was $781.4{;}{pm}{;}119.3m{ell}/day$ and that of formula was $848.6{;}{pm}{;}118.5m{ell}/day$. Mean apparent digestible energy intakes of formula-fed infants and breast-fed infants during 3months were 568.9 $pm$146.9 kca1/day and 657.9$pm$212.8 kca1/day, respectively. The average protein intake of brest-fed and formula-fed infants were 8.3$pm$1.6g/day and 14.1$pm$14.1 g/day, respectively. The protein intakes of formula-fed infants were significantly higher than those of breast-fed infants at 1, 2, 3 months. The apparent protein digestibility of breast-fed infants was singnificantly higher compared to formula fed infant. These data suggest that RDA for infants be established and breast feeding be encouraged.