Background Idiopathic rapid eye movement sleep behavior disorder is associated with increased risk of neurodegeneration, but the temporal evolution of regional perfusion, a marker of cerebral activity, has not been characterized. The objective of the current study was to study longitudinal regional perfusion in patients with idiopathic rapid eye movement sleep behavior disorder. Methods Thirty‐seven patients and 23 controls underwent high‐resolution single‐photon emission computed tomography. After 17 months on average, scans were repeated for idiopathic rapid eye movement sleep behavior disorder patients. We compared regional cerebral blood flow between groups and over time. Results At baseline, patients showed lower relative regional perfusion in the anterior frontal and lateral parietotemporal cortex compared with controls. However, over time, patients showed an increase in relative regional perfusion in the anterior frontal, lateral parietal, and occipitotemporal cortex, reverting toward normal control levels. Conclusions Patients with idiopathic rapid eye movement sleep behavior disorder showed significant areas of relative regional hypoperfusion, which disappeared over time to finally return to average levels, suggesting possible developing compensation in areas affected by neurodegeneration. © 2020 International Parkinson and Movement Disorder Society