This chapter considers nutritional requirements of the neonate during the period between birth and weaning. Requirements comprise whatever is necessary to maintain normal healthy body functions, daily energy expenditure above maintenance, and growth. Exclusive breast-feeding to 6 months meets all of the protein requirements of the healthy baby. Milk fat provides more than half of the neonate's dietary energy; and individual fatty acids play an important role in neonate's growth and development. Lactose is the principal carbohydrate in breast milk and makes a significant contribution to energy supply. Through provision of glucose, it is essential for brain and nervous tissue function. Fluid requirements are stated to increase from approximately 100ml/kg/day at birth to approximately 150ml/kg/day at 6 months. Calcium levels in breast milk are less than one third of cow's milk levels, and formula is intermediate, but the absorption of calcium from breast milk is higher than that from formula.