We found dyskinetic strabismus in 66 patients with cerebral palsy. The most striking feature of dyskinetic strabismus is the fluctuation from esotropia to exotropia under the same accommodative conditions with a slow tonic deviation similar to a vergence movement. With increasing age, exodeviation becomes more prevalent. Dyskinetic strabismus is seen exclusively in cerebral palsy patients. Many of these patients have an athetoid component to their disorder. The association of dyskinetic strabismus with athetosis and upward gaze palsy suggests that the basal ganglia may be the site of the malfunction. The strabismus responds poorly to surgery and the associated athetosis is important in the diagnosis and treatment of cerebral palsy.