Malignant hyperthermia is a hypermetabolic, fatal syndrome triggered by anesthetic drugs that occurs frequently in genetically susceptible persons. It is characterized by tachycardia, rapidly increasing temperature, skeletal muscle rigidity, respiratory and metabolic acidosis, cyanosis etc. It has been noted that the majority of cases of malignant hyperthermia are fatal unless early diagnosis and treatment are performed Thus, the accurate prediction of preanesthetic susceptibility and early diagnosis of malignant hyperthermia is necessary to appropriate treatment. Dantrolene sodium has been shown to be effective in the prevention and treatment of malignant hyperthermia. We experienced a case of malignant hyperthermia, which is presented of a 32-year-old healthy male patient in whom a orthognatic surgery was performed under O2-N2O-enfl-rane anesthesia with induction by pentobarbital and succinylcholine. We discuss this case with reviewing the history, incidence, etiology, pathophysiology, clinical signs & biochemical changes, prevention & treatment.