Preterm infants are a neonatal population with increased risk of morbidity and mortality. The major interest in preterm care is brain function and its association with neurodevelopmental outcome. The principal method for monitoring brain function is electroencephalography, especially when adjusting medication for epileptic activity. An easier and more straightforward way to ascertain brain function is amplitude-integrated encephalography. Caregivers use amplitude-integrated encephalography in many clinical scenarios, including assessment of neonatal encephalopathy, monitoring of seizures, detection of intraventricular hemorrhages, and prediction of long-term development. In neonatal intensive care units around the world, caregivers widely use amplitude-integrated encephalography, and researchers are constantly discovering novel applications for this technology.