Reversible posterior leukoencephalopathy syndrome is a recently described disorder with typical radiologic findings in the posterior regions of the cerebral hemisphere and cerebellum. The symptoms include headache, nausea, vomiting, visual disturbances, focal neurologic deficits, and seizures. A 10-year-old male was hit on his back, resulting in backache. He was medicated with sodium diclofenate and mefenamic acid. The next day, he had edema and oliguria. By the third day, his blood pressure increased and he began to experience restlessness and worsening mental status. He then complained of headache and visual disturbances and had a seizure. A magnetic resonance imaging scan revealed abnormalities in the posterior regions of the cerebral hemisphere and cerebellum. The patient was treated with antiepileptics and calcium antagonists. His hypertension and seizures were well controlled. On the 22nd day, he was discharged without any neurologic or renal deficits. Reversible posterior leukoencephalopathy syndrome does not occur frequently in childhood, and this is the first case report of reversible posterior leukoencephalopathy syndrome related to nonsteroidal anti-inflammatory drugs. One should consider reversible posterior leukoencephalopathy syndrome as a side effect of nonsteroidal anti-inflammatory drug use in daily medical treatment.