Data have been collected by the Australian and New Zealand Neonatal Network (ANZNN) to improve the care of high-risk newborn infants and their families in Australian and New Zealand through collaborative audit and research. This is the seventeeth year that the ANZNN has collected data, allowing comparative reporting over time.Registration criteria - babies who meet one or more of the following criteria are eligible for registration with the ANZNN:* born at less than 32 weeks gestation, or* weighed less than 1,500 grams at birth, or* received assisted ventilation (mechanical ventilation) including intermittent positive pressure ventilation (IPPV) or continuous positive pressure (CPAP) or high flow for four or more consecutive hours, or died while receiving mechanical ventilation prior to four hours of age, or* received major surgery (surgery that involved opening a body cavity), or* received therapeutic hypothermia.Babies who were discharged home and readmitted to neonatal intensive care unit (NICU) during their neonatal period were not eligible for registration in the ANZNN. The hospital of registration was the first level III NICU in which the baby, aged less than 28 days, stayed for four or more hours. Babies who received their entire care in a level II hospital or who were not transferred to a level III NICU during the first 28 days were registered to the first level II centre that they remained in for four or more hours.In 2011, there were 7,412 babies from 22 level III NICUs in Australia and 1,770 babies from six level III NICUs in New Zealand registered to ANZNN. In 2011, 769 babies fulfilled the ANZNN criteria for registration to 22 level II units in Australia and New Zealand.Data in this collection include:maternal characteristics (maternal age, previous antenatal history, assisted conception, presenting antenatal problem, antenatal corticosteroid use, multiple births, method of birth, place of birth, transport after birth to a level III NICU and breastfeeding at discharge) and baby's characteristics (baby gender, resuscitation in delivery suite, apgar score at birth, admission temperature, indication for respiratory support, exogenous surfactant, type of assisted ventilation, ventilation in babies born at less than 32 weeks gestation, ventilation in babies born at 32 to 36 weeks gestation, ventilation in babies born at term, supplemental oxygen therapy, chronic lung disease, pulmonary air leak, neonatal sepsis, retinopathy of prematurity, intraventricular haemorrhage, late cerebral ultrasound, necrotising enterocolitis, congenital anomalies, transfer from level III NICUs to other units, length of stay until discharge home and survival of the ANZNN registrants).