The clinical cases of 6 patients suffering with chorea after acute carbon monoxide (CO) poisoning were reviewed. There were 2 men and 4 women, and the age at onset ranged from 11 to 60 (mean 33.0) years. All the patients except one were associated with mild delayed CO encephalopathy. The latency period between CO poisoning and the onset of chorea was 10 to 30 (mean 21.7) days. The duration of chorea after CO poisoning was 14 to 90 (mean 39.8) days. The brain CT findings were bilateral low- density lesions in the basal ganglia and/or in the white matter of the cerebral cortex, and there was no correlation between the lesion sites on the imagings and the development of chorea.