Infants born prematurely are highly vulnerable to brain injury and susceptible to seizures in the first weeks of life. Many neonatal seizures occur without reliable clinical signs and are detectable only on electroencephalogram (EEG); understanding EEG findings in these neonates is crucial for providing appropriate care. This can be challenging, as EEG background activity and patterns vary considerably with gestational age. Some physiologic preterm EEG patterns, such as rhythmic temporal theta activity or delta brushes, may be sharply contoured and appear similar to epileptic EEG patterns later in life. Moreover, ictal patterns in preterms are of lower voltage and frequency than in full-term neonates. This article reviews current data on incidence of seizures in preterms and their typical ictal EEG patterns. It also identifies the pitfalls of EEG analysis in a neonatal intensive care unit environment and gives examples of typically observed artifacts. It then discusses the impact of seizures on long-term outcome of preterms, independent of other variables such as gestational age and brain injury. Finally, it suggests future directions for research in preterm seizures.