A 68-year-old man was hospitalized on 24 June, 1998 because of visual and gait disturbance. A month before admission, he had been aware of blurred or double vision while watching TV. A few days later, he developed dysphagia and clumsiness in the fingers. His gait became unstable and he exhibited restless finger movements. His shoulders and trunk showed torsion while walking. On admission, he became disoriented and showed rigidity in the legs and athetosis in the bilateral fingers. Routine laboratory findings, thyroid function data, and the serum levels of vitamin B1, B12, Cu, and ceruloplasmin were within the normal ranges. Periodic synchronous discharges (PSD) were observed on electroencephalography. MRI showed T2-high intensity and atrophy of the bilateral caudate nucleus and putamen in addition to the cerebral cortex. 99mTc-ECD-SPECT showed a decrease of local blood flow in the bilateral frontal, right temporal, and bilateral parietal lobes and bilateral thalami. Athetosis became exacerbated and was observed for a month, overlapping with myoclonus. We diagnosed the patient as having CJD because of progressive dementia, myoclonus and PSD. Analysis of the prion protein revealed that codon 129 was Met/Met and codon 219 Glu/Glu by DNA sequences. The patient developed akinetic mutism and rigid contracture, and died of pneumonia on 5 September, 1998. Because athetosis is thought to involve the bilateral caudate nucleus, putamen and thalamus, the findings of diagnostic imaging in this patient might be relative to the clinical symptoms.