A 50-year-old man (weight 87 kg, height 171 cm) with myasthenia gravis (MG) was scheduled for extended thymectomy under general anesthesia. His preanesthetic train-of-four ratio (T4/T1) was 59%. The first twitch of the train-of-four (T1) was 130% after calibration. We administered rocuronium 10 mg (0.11 mg x kg(-1)) for tracheal intubation. Maximal suppression was achieved in 50 seconds. During the operation, we did continuous infusion of rocuronium to maintain T1 at 10%. We discontinued rocuronium infusion before the end of surgery. In patients with MG, deep levels of neuromuscular block can be achieved with less rocuronium. We hypothesized that the requirement of sugammadex in a patient with MG is less than that in normal patients. Therefore, we administered 0.5 mg x kg(-1) of sugammadex. After 5 min, T4/T1 had reached 54%, but T1 had not reached the control value; therefore, we administered additional 1.5 m x kg(-1) of sugammadex. Subsequently, T1 reached 120%. Patients with MG with fade on T4/T1 require a full dose of sugammadex, identical to the dose administered to normal patients.