Summary: Neonatal seizures frequently accompany neonatal encephalopathies. Seizures occur in ∼1.8–5/1,000 live births in this country and are caused by virtually any condition that affects neonatal brain function. This review provides a simple classification of seizures and emphasizes that many abnormal intermittent behaviors in this age group are not accompanied by ictal EEG patterns. Additionally, ≤50% of neonatal seizures are not associated with abnormal clinical behavior. This is a common phenomenon, particularly after anticonvulsant treatment in which the clinical seizures are suppressed but electrographic seizures continue unabated. Seizures also may be caused by genetic disorders, several of which are benign, familial, and caused by channelopathies involving potassium channels. The review also discusses the epileptic syndromes seen in neonates, including early myoclonic encephalopathy, Ohtahara syndrome, pyridoxine dependency, and glucose transporter type 1 syndrome.