This chapter discusses the case of an 8-year-old female who was admitted to a pediatric neurology clinic for evaluation of chronic sleep-related behaviors that were unresponsive to anticonvulsant treatment. It presents the clinical history, examination, follow-up, treatment, diagnosis, and the results of the procedures performed on the patient. The combination of polysomnography (PSG) and clinical history led to a diagnosis of both somnambulism (sleepwalking) and seizure disorder. The possibility that her sleepwalking episodes were representative of partial complex seizures or prolonged postictal states cannot be ruled out given the relative limitations of the evaluation. The EEG concomitants of an active seizure have classically included generalized depression or slowing, rhythmic slow-wave or spike/polyspike and wave activity that can occur immediately prior to or during an event, and postictal slowing or depression frequently following a spell. Video recording and response to treatment aid in making a diagnosis of probability.