The neuroleptic malignant syndrome is an uncommon but occasionally fatal reaction to antipsychotic medication characterized by fever, movement disorder, and stupor. A case is reported of a 16-year-old retarded male who progressed into coma after an injection of fluphenazine. The syndrome is discussed, and new pharmacological treatment approaches are reviewed. Brain-damaged patients are thought to be more susceptible to this syndrome. As recognition of the syndrome grows, there may well be more cases identified in the mentally retarded population.