The impact of premature birth can be lifelong, and although the risk of acute complications reduces throughout infancy and early childhood, long-term morbidity remains high. Low gestational age at birth is an independent risk factor for increased mortality from respiratory, cardiovascular, endocrine and congenital disorders in childhood and early adulthood. This chapter describes the definitions and risk factors of prematurity and the clinical manifestations unique to the premature infant, including thermoregulatory instability, respiratory distress syndrome and bronchopulmonary dysplasia, apnoea of prematurity, patent ductus arteriosus, necrotising enterocolitis, intraventricular haemorrhage and retinopathy of prematurity. The preoperative, intraoperative and postoperative considerations for management of these vulnerable infants will be discussed. Finally, the conduct of anaesthesia in the ex-premature infant will be described and key points highlighted.