In this case report, we describe separate instances of general anesthetic management administered to a patient during treatment for two unrelated conditions. The patient, a 57-year-old woman who had been experiencing walking difficulties for about four years, fell down because of muscle rigidity and spasms and fractured her humerus. She was subsequently diagnosed with stiff-person syndrome. The fracture was treated conservatively, but three weeks later the alignment of the humerus became worse and the patient was scheduled to undergo an open reduction and internal fixation under general anesthesia (GA). Anesthesia was induced using propofol and fentanyl, and rocuronium was given for the tracheal intubation. The operation was completed successfully while anesthesia was maintained using sevoflurane and remifentanil without incident Four months later, the patient developed paraneoplastic syndrome stemming from breast cancer, and underwent a resection of the cancer under GA. The patient received propofol for the laryngeal mask insertion, and sevoflurane and pentazocine for maintenance of anesthesia. She was discharged from the hospital without any respiratory or airway problems. We used sevoflurane for maintenance of anesthesia on both occasions, and rocuronium for the first tracheal intubation. The patient's hemodynamics were stable during the operation. No prolonged effect of the muscle relaxant or any autonomic reactions were observed. The patient was fully conscious and in good respiratory condition after both surgeries, and was extubated in the operating room. There were no perioperative complications.