We performed two successive operations in a 39-year-old pregnant woman with myasthenia gravis (MG) with perioperative administration of dexmedetomidine. The first was an emergency cesarean section at 28 weeks' gestation. The patient was administered vecuronium, a muscle relaxant during the operation. She was sedated with dexmedetomidine for prolonged postoperative intubation until she was conscious and the effects of vecuronium had worn off. Extubation was successfully performed within half an hour of regaining consciousness. The second operation was an extended thymectomy performed under general anesthesia. Dexmedetomidine was administered intravenously as an adjunctive anesthetic without vecuronium. Extubation was successfully performed immediately after the operation. Here, we report a successful perioperative management with dexmedetomidine in a patient with MG, without any complications. Although dexmedetomidine has been considered useful for perioperative management of patients with MG, further consideration regarding its use in such cases is needed.