Breastfeeding is the healthiest way for a woman to feed her infant. The World Health Organization/United Nations International Children's Emergency Fund ( 1989 ) launched the Baby-Friendly Hospital Initiative to protect, promote and support breastfeeding in maternity services. However, this initiative focuses on healthy and full-term infants. While it remains the role of the nurse in children's hospitals and neonatal/children's units to promote, protect and support mothers to breastfeed sick and premature infants, this is performed in an environment that incorporates the unexpected nature of these infants' sickness/prematurity. In children's hospitals and neonatal/children's units, breastfeeding is challenged by infant's illness, prematurity, fasting or maternal/infant separation, resulting in mothers expressing their milk for their infants to consume either through alternative routes immediately or freezing it for a later date. Furthermore, once clinically stable, these mothers and infants should be afforded the opportunity to safely and effectively transition from expressed breast milk to direct breastfeeding. For the purpose of this article, the infant population of children's hospitals and neonatal/children's units is comprised of either an infant transferred from a maternity unit at birth due to illness/prematurity or an infant admitted up to the age of one year.