BACKGROUND Preeclampsia and eclampsia have been associated with significant morbidity and mortality. Posterior reversible encephalopathy syndrome is a neuroradiologic entity that has been previously reported to occur in patients with preeclampsia and eclampsia. We present, to our knowledge, the first reported case of late postpartum eclampsia complicated by posterior reversible encephalopathy syndrome and reversible cerebral herniation. METHODS A 39-year-old woman (para 1) presented with late postpartum preeclampsia on postpartum day 4. She developed eclampsia and posterior reversible encephalopathy syndrome, which was diagnosed by magnetic resonance imaging. She subsequently developed clinical and radiologic evidence of reversible cerebral herniation. CONCLUSIONS Postpartum preeclampsia and eclampsia that is complicated by posterior reversible encephalopathy syndrome can result in cerebral herniation. Neuroradiologic imaging may be a useful adjunctive diagnostic tool in the setting of preeclampsia and eclampsia to predict disease severity.