Reversible posterior leukoencephalopathy syndrome (RPLS) is a recently identified clinical and radiologic entity. The characteristic radiologic findings are bilateral gray and white matter edema in the posterior regions of the cerebral hemispheres. The typical clinical syndrome includes headache, confusion, visual symptoms, and seizures. RPLS most often occurs in the setting of hypertensive crisis, preeclampsia, or with cytotoxic immunosuppressive therapy, but many other clinical settings are described, such as cryoglobulinemia, hemolytic uremic syndrome, systemic lupus erythematosus, and use of erythropoietin. A 24-year-old man, diagnosed as having anaphylactoid purpura nephritis at 12 years of age and who started peritoneal dialysis (PD) at 23 years of age, was admitted to our hospital with a seizure and consciousness disturbance. His blood pressure (BP) and body fluid volume had not been controlled well because of poor compliance with medication and PD. T2-weighted magnetic resonance imaging (MRI) revealed high signal intensity changes restricted to the cortex and subcortical white matter of the cerebellum. On the other hand, diffusion-weighted imaging showed an isointense signal. From these findings, he was diagnosed as having RPLS. With appropriate control of BP and volume control by PD and hemodialysis, his symptoms improved, and a follow-up cranial MRI 1 month later was almost normal. To the best of our knowledge, this is the first report of RPLS in an adult PD patient.