Myasthenia gravis is usually defined as a state of abnormal fatigability. The cause of myasthenia gravis is not known. Several disorders tend to occur more frequently in patients with myasthenia gravis, such as hyperthyroidism or other thyroidal disorder. Anesthetic experience with thymectomies for two patients with myasthenia gravis has been reported. Both of them tolerated the surgical procedures under endoteracheal Nitrous oxide-Oxygen-Halothane anesthesia well. Diagnosis and clinical features including choice of preanesthetic medication, anesthetic agents, techniques and of neuromuscular blocking agents for myasthenic patients have been discussed. Paramount importance of rigid attention to ventilation, the maintenance of a patent airway and the removal of secretions whenever necessary for the patient safety throughout operative and postoperative period has been stressed.