Paroxysmal vertical ocular dyskinesia of a previously undescribed nature is reported in a 42-year-old woman with demyelinating disease, who was affected with a myelopathy, bilateral amblyopia, and a modified sylvian aqueduct syndrome. Electroencephalography, electronystagmography, and cinematography techniques were used to study this phenomenon. This eye movement disorder is distinct from, but related to, other forms of ocular dyskinesia.