Acute catatonic syndrome is a condition that can be caused by a variety of metabolic, neurological, psychiatric, and toxic conditions, including neuroleptic malignant syndrome. Although ictal catatonia as a manifestation of non-convulsive status epilepticus has been described, reference to the occurrence of seizures in patients with acute catatonic syndrome is anecdotal. Twenty nine patients with acute catatonic syndrome were reviewed to identify patients with seizures after the onset of acute catatonic syndrome. Patients were divided into four diagnostic groups: affective (15), schizophrenic (eight), toxic (two), and organic (four). Seizures occurred in four patients (13.8%): two patients with dystonic seizures had viral encephalitis and schizophrenic disorder respectively; one patient with complex partial seizures had viral encephalitis and one patient with absence status had neuroleptic malignant syndrome. The results indicate the value of EEG in detection of epileptic activity in patients with acute catatonic syndrome, both at onset and in the course of such disturbance, particularly to provide a differential diagnosis between pseudo-seizures and neuroleptic-induced acute dystonia.