A 35-year-old patient experienced 2 months, low levels of carbon monoxide exposure, produced by the motor of his vehicle. He experienced drowsiness in the morning. Because of drowsiness he had an automotomobile accident with traumatic brain injury. The only symptom at the time of neurological examination was anterograde amnesia. The magnetic resonance (MRI) of the brain revealed bilateral necrosis of the globus pallidus. We present this case for prevention of carbon monoxide poisoning and as an example of the utility of MRI and neuropsychological examinations in detecting central nervous system dysfunction secondary to CO exposure.