Posterior reversible encephalopathy syndrome (PRES) is a unique clinical entity. Clinical manifestations typically involve headaches, visual changes, seizure and altered mental status. Imaging findings may not be restricted to the posterior-circulation. There are many diseases associated with PRES. The pathogenesis of PRES is still not entirely clear. Two controversial hypotheses have been proposed: hypertension leading to the breach of blood-brain barrier vs. endothelial injury. We will discuss the clinical, radiological and electrographic features of PRES as well as prognosis for seizures.