A case of acute encephalopathy with posterior corticosubcortical vasogenic edema on magnetic resonance imaging is reported. Angiography showed cerebral arterial vasospasm. A diagnosis of acute post-streptococcal glomerulonephritis was made 2 days after admission. This report highlights the fact that acute post-streptococcal glomerulonephritis can be revealed by a posterior reversible encephalopathy syndrome and that cerebral vasospasm can concur with vasogenic edema in this condition.