Anesthetic experience with thymectomies for two patients with myasthenia gravis has been reported. Both of them talerated the surgical procedures under endotracheal nitrous oxide-oxygen-halothane anesthesia well, but one of tbem expired from cholinergic crisis on the 3rd postoperative day. Chemical diagnosis of myasthenia gravis and the salient 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 by bronchoscopy or tracheostomy whenever necessary for the patient safety throughout operative and postoperative period has been stressed. Frequent determinations of pulmonary function and the use of edrophonium test in avoiding cholinergic crisis are advocated.