Korean breast-fed(BF) and formula-fed (FF) infants(n=31) were studied at their age of 1, 2 and 3 months to compare their intakes of energy, protein, lipid and lactose. Formulas had more energy, protein and lipid than breast milk, but the former had less lactose than the latter. The milk consumption of the FF infants was, however, greater than that of the BF infants with wide individual variation. As a result, the FF infants took in more energy, protein and lipid than the BF infants except lactose. The total daily caloric intakes(kcal/day) of the BF infants were 521.418 and 425 at their age of 1, 2 and 3 months respectively, and those of the FF infants were 676.752 and 723(at their age of 1, 2 and 3 months respectively). Daily protein intakes(g/days) of the BF infants were 9.5, 8.0 and 7.6 at their age of 1, 2 and 3 months respectively, and those of the FF infants were 13.9, 15.5 and 14.8(at their age of 1, 2 and 3 months respectively). The energy and protein of both the BF and the FF infants were deficient compared to the present Recommended Nutrient Allowances, and the deficiency of the BF infants was greater than that of the FF infants. But the energy intakes per kg of body weight of the FF infants at their age of 1 and 2 months were more than the present recommended energy allowances. And the protein intake per kg of body weight of the FF infant at the age of 1 month was the same as the present recommended protein allowances.