The neuropathologic sequelae of carbon monoxide (CO) toxicity have been well described in postmortem examinations. Globus pallidus damage as well as diffuse white matter lesions and encephalopathic changes occur. Brain CT has provided imaging correlates to the premortem changes. MRI is more sensitive and provides more specificity. Cerebral edema changes may occur early with subsequent demonstration of globus pallidus lesions and white matter changes. Globus pallidus lesions in many cases do not correlate directly to clinical status and outcome; however, the presence of diffuse white matter disease is a more reliable index of both. These changes are seen in patients in both accidental exposures to CO and in suicide attempts.