Parkinsonism is a common neurological sequela of carbon monoxide (CO) poisoning, but its pathophysiological mechanism has yet to be clarified. Objectives: To describe a married couple who were both affected by CO poisoning, but only 1 of whom developed CO-induced parkinsonism, and to discuss the possible underlying pathophysiological mechanism of COinduced parkinsonism by comparing the neuroimaging findings of these patients. Design and Setting: Case report from a clinical neurology department.