Lethal catatonia, a life-threatening febrile neuropsychiatric disorder, was widely reported in this country and abroad before the introduction of modern psychopharmacologic treatments. A comprehensive review of the world literature indicates that although the prevalence of lethal catatonia may have declined, it continues to occur, now reported primarily in the foreign literature. Lack of recognition probably accounts for the scarcity of recent American reports. Furthermore, lethal catatonia is a syndrome rather than a specific disease and may develop in association with both functional and organic illnesses. Familiarity with the clinical features and varied etiologies is essential for effective management of this catastrophic reaction.