We report a case of head injury with posterior reversible encephalopathy syndrome (PRES), followed by Guillain-Barré syndrome (GBS). A 74-year-old man was brought to our hospital after a fall. Computed tomography revealed intracranial hemorrhage. Magnetic resonance imaging showed bilateral reversible intensities with features of vasogenic edema in parietooccipital areas, suggesting PRES. After admission, weakness and areflexia of extremities and respiratory muscles developed gradually, which favored a diagnosis of GBS. Common etiologies of PRES were absent. Concurrent occurrence of PRES and GBS is rare. Given that PRES can be an initial manifestation of GBS, GBS must be considered in head trauma patients with PRES.