Reversible posterior leukoencephalopathy syndrome (RPLS) was described by Hinchey and colleagues in 1996. The disorder occurs predominantly in patients with acute hypertension and/or on pharmacological immunosuppression. We report a 6-year-old male with cerebral X-linked adrenoleukodystrophy who received an HLA-matched unrelated bone marrow transplant (BMT). Cyclosporine was used as graft-versus-host disease prophylaxis. At 55 days post-BMT, his cyclosporine concentrations were high for several days and the concentration was still high on day 70 (353 microg/L). He presented 83 days post-BMT with new onset of headache, lethargy, acute visual loss and focal seizures. He was not hypertensive. MRI of the head revealed signal changes that now extended more peripherally into the subcortical and cortical regions of the occipital and temporal lobes. The patient's cyclosporine was stopped for 5 days. The patient's vision returned to normal and his headaches and lethargy resolved with no further seizures 3 weeks later. Follow-up MRI of the head 2 months later showed almost complete resolution of the cortical signal abnormalities. It is important to consider RPLS in patients with cerebral adrenoleukodystrophy who present with acute neurological deterioration. Attention to the pattern of white matter and the presence of cortical grey matter involvement on neuroimaging is important for the diagnosis. When appropriate management is initiated, that is controlling hypertension when present and discontinuing or reducing the dose of offending immunosuppressive agents, the acute neurological symptoms will usually resolve.