We report the anesthetic management of a narcoleptic patient performed using sevoflurane-remifentanil with bispectral index (BIS) monitoring. A 22-year-old man, who was diagnosed with narcolepsy at the age of 17, requested endoscopic sinus surgery, under general anesthesia, for chronic allergic rhinitis. On the morning of the day of operation, he took his daily dose of modafinil, used to control narcolepsy. Anesthesia was induced by 5% sevoflurane and maintained with sevoflurane and continuous infusion of remifentanil and 60% oxygen in conjunction with BIS monitoring. BIS values were between 47 and 58. Duration of surgery was 150 min. After surgery, the patient emerged from anesthesia within 10 min and was extubated. His recovery was uneventful. We found the use of BIS monitoring for titrating sevoflurane concentration in a narcoleptic patient is useful for preventing not only oversedation but also intraoperative awareness caused by the preoperative medication.