The authors report a case of hemichorea-hemiballism (HC-HB) that was successfully treated using deep brain stimulation (DBS). A 65-year-old right-handed man exhibited a sudden onset of right HC-HB without a diabetic coma. At admission T1-weighted magnetic resonance (MR) images revealed a high-intensity signal in the left striatum, contralateral to the patient's involuntary movements. The HC-HB continued for 5 months after onset of the condition despite medical treatment and a decreased intensity of the signal on T1-weighted MR images. The patient underwent placement of a quadripolar DBS electrode in the left thalamus, including the left ventral oralis (VO) anterior and posterior nuclei (the VO complex). Postoperatively, the right-sided HC-HB disappeared rapidly during electrical stimulation and there were no neurological deficits. The authors demonstrate that DBS can be an effective treatment for medically refractory HC-HB. This is the first case of HC-HB that has been successfully treated with DBS.