Neuroleptic malignant syndrome (NMS) is an uncommon potentially fatal side effect of neuroleptic drugs, characterized by movement disorder, altered mental status and autonomic instability. A single dose of clotiapine was administered to an 11-year old male with acute psychosis. The previously healthy child had signs consistent with NMS including hyperthermia, hypertension, motor and mental changes. Repeat examination performed two weeks later, demonstrated that while his hyperthermia subsided, his mental status deteriorated. Olanzapine was administered, after which the child had hyperthermia, dystonia and more pronounced restlessness, once again consistent with NMS. He developed respiratory failure and was intubated and mechanically ventilated. Lorazepam, dantrolene and bromocriptine were administered as treatment of possible NMS. His mental condition, movement disorder and autonomic dysfunction improved significantly. Two weeks later, the patient was discharged in good general condition without the need for any ongoing medical treatment. There are only few case reports of NMS in children treated with olanzapine, an atypical antipsychotic. In children, caution must be exercised when prescribing antipsychotics, particularly atypical antipsychotics as these drugs may cause NMS. Because of the low incidence of NMS, a high index of suspicion is needed to identify cases so prompt treatment can be undertaken.