Neuroleptic Malignant Syndrome (NMS) is usually seen in patients who use antipsychotic drugs and has a high mortality rate. It is a life-threatening con- dition associated with dopaminergic blockage. Symptoms include high fever, diaphoresis, unstable blood pressure, unconsciousness, muscular rigidity, and autonomic dysfunction. The 46-year-old male patient who had a history of 10 years of klozapin use due to schizophrenia applied to the emergency ser- vice with unconscionsness, speech disorder and high fever. Having a history of irregular use of medicine in the recent past, the patient was restarted with klozapin as his symptoms increased. During the neurological examination, he had impaired consciousness and muscular rigidity. The laboratory analysis revealed the leukocyte 13.800/mm3, AST: 2.067 U/L, ALT: 295 U/L, LDH: 5.709 U/L, CK-MB: 1.189 U/L, CK: 123.889 U/L. He was diagnosed as NMS. By presenting this case, we aim to discuss the approaches to NMS and treatment modalities of NMS in light of the literature.