Bilateral globus pallidus necrosis is said to be characteristic of carbon monoxide (CO) poisoning. However, there has been no scientific test of this hypothesis. To examine the assertion that globus pallidus necrosis is typical of CO poisoning, this study examined autopsy cases from the King County Medical Examiner's Office (KCMEO) between 1994 and 2013. Twenty‐seven cases with bilateral basal ganglia lesions were identified and examined for associated or causative disease or injury with the following results: 10 cases of drug overdose, seven heart disease, three asphyxia, two chronic ethanolism, two Huntington‐like disorder, and one case each of remote trauma, rheumatic heart disease, and cerebral artery gas embolism. Additionally, review of all known cases at KCMEO of CO poisoning found no evidence of globus pallidus or basal ganglia necrosis. Thus, this study provides no support for the assertion that globus pallidus necrosis is characteristic of CO poisoning.