An electroencephalogram (EEG) is a critical tool in epilepsy diagnosis. The three common EEG durations are 25 minutes, 1 hour, and 24 hours. One-hour EEGs are superior in showing epileptiform abnormalities, while 24-hour EEGs are used to characterize seizure and nonepileptic event semiology and guide treatment of status epilepticus. The term EEG montage refers to the way EEG electrodes are ordered for interpretation. Odd numbered electrodes are on the left, with even numbered on the right. Smaller numbers are closer to the midline, while z means the electrode is on the midline.This chapter will explore the numerous normal and variant findings like posterior dominant rhythm (PDR) and wicket spikes. Epileptiform findings like sharp waves or seizure patterns are indicative of epilepsy. Slowing or increased amplitude can indicate cerebral changes that are not epileptiform.Electroencephalogram reports should concisely accurately convey both the electrical findings and their clinical relevance to patient care. Electroencephalogram reports should indicate an epilepsy diagnosis only when clear electrical evidence exists.