A 31-year-old man with psychosis and neuroleptic-induced tardive dystonia developed neuroleptic malignant syndrome (NMS) while taking haloperidol. Muscle rigidity responded to dantrolene, but hyperthermia did not abate until therapy with carbidopa/levodopa was initiated, after which temperature varied in direct relationship to subsequent levodopa administration. This supports the role for central dopaminergic mechanisms in the pathogenesis of NMS.