A 29-year-old woman developed diplopia and ataxic gait. Neurological examination revealed total ophthalmoplegia, cerebellar ataxia, and areflexia. Muscle weakness in four limbs was also noted. We diagnosed the patient as having an overlap between Fisher's syndrome and Guillain-Barré syndrome. On day 5, she suddenly had flinging involuntary movements affecting the face and four extremities. Surface EMG recording revealed 1.5- 2 Hz rhythmic grouping discharges. The involuntary movements were considered as ballism. Brain CT and MRI could not detect any abnormal findings in subthalamic nucleus, but, electrophysiological findings revealed CNS lesions. Therefore, the clinical diagnosis also were Bickerstaff's brainstem encephalitis. She had high titer of IgG antibody to GQ 1b (1:64,000). Sera taken from patients with Fisher's syndrome, Guillain-Barré syndrome with ophthalmoparesis and Bickerstaff's brainstem encephalitis during the acute phases of these syndromes frequently have IgG antibody to GQ 1b ganglioside. It is concluded that some cases of acute ophthalmoparesis subsequent to infection or immunization may be categorized as autoimmune diseases. Hence, such disease which show external ophthalmoparesis may be designated the "anti-GQ 1 b IgG antibody syndrome". This is the first report on the patient with Guillain-Barré syndrome and the related disorders who showed ballism.