The popular term malignant hyperthermia syndrome (MHS) refers to a clinical syndrome classically observed during general anesthesia. It is characterized by a rapidly increasing .temperature and a high mortality rate. A case of MHS was experienced which developed 60 minutes after induction of general anesthesia with thiopental sodium, succinylcholine, halothane, N2O and 02. High fever, muscle rigidity and cyanosis developed and were followed by arrythmia and unstable blood pressure. Anesthesia was terminated and vigorous emergency treatment was attempted. The patient died about 6 hours after induction of anesthesia.