Posterior reversible encephalopathy syndrome (PRES) is a clinically and radiologically defined syndrome characterized by seizures, headaches, visual disturbances, and altered mental status or focal neurological deficits. Imaging frequently shows abnormalities in the posterior brain regions, especially the occipital and the parietal lobes. PRES has been described in association with a wide spectrum of underlying causes. The most common conditions include hypertension, renal disease, preeclampsia/eclampsia, or status post transplantation. The pathophysiology of PRES has not been sufficiently elucidated as yet; however, endothelial damage caused by different mechanisms possibly plays a central role. The prognosis of PRES is usually benign when intensive care and withdrawal of the causative agent is instituted early. Delay in diagnosis and treatment may lead to complications and permanent neurological deficits. The clinical and radiological landmarks of this syndrome as well as causes, pathophysiological hypotheses, and the basic therapeutic principles of PRES are the subject of the present review.