Two young women who had encephalopathy that resembled reversible posterior leukoencephalopathy syndrome are presented. The brain magnetic resonance imaging (MRI) of these patients exhibited similar T2-high signal lesions, mostly in the white matter of the posterior hemispheres. Xe-SPECT during the patients' symptomatic period showed hypoperfusion in the corresponding areas, and angiography demonstrated irregular narrowing of the posterior cerebral artery. Clinical manifestations subsided soon after treatment, and the abnormal radiological findings also were almost completely resolved. Thus, we concluded that transient hypoperfusion followed by ischemia and cytotoxic edema might have had a pivotal role in these cases.