Infant formulae are the only alternatives to breast milk for infants who are unable to continue breastfeeding through the first year of life. They aim to provide formula-fed infants with the same structural and functional benefits observed in breastfed infants. To achieve this, bioactive nutrients have been added to infant formulae in recent years: long-chain polyunsaturated fatty acids for neurodevelopment; probiotics and prebiotics for local gastrointestinal defence; and nucleotides for promoting the immune response. Changes in protein quantity and quality allow infant formulae to achieve a balance between providing the correct plasma amino acid profile and reducing the protein intake, which could prevent obesity in later life. Hydrolysed proteins may help prevent atopic disorders. Many short-term trials have been published but long-term follow-up data are needed in infants who have been fed the newer infant formulae, to fully understand the role of bioactive nutrients.