Rhabdomyolysis is one of the perioperative complications in patients with Duchenne's muscular dystrophy (DMD). It has been suggested that sevoflurane can be used safely for anesthesia in patients with DMD. In this report, we describe a case with DMD who received anesthesia with sevoflurane, in which rhabdomyolysis developed postoperatively. A 6-year-old boy diagnosed as DMD was scheduled for tonsillectomy under general anesthesia. Preoperative laboratory examination revealed a high level of creatine kinase (CK) (16,000-32,000 IU.l-1). An abnormality of the dystrophin gene was detected by DNA analysis. Anesthesia was induced with sevoflurane without muscle relaxant, and maintained with sevoflurane in nitrous oxide and oxygen under controlled ventilation. The course of anesthesia was uneventful and the patient recovered smoothly. Three hours postoperatively, dark red urine with a high concentration of myoglobin (1,390,000 ng.ml-1) was recognized with a high level of CK (63,500 IU.l-1). Body temperature was 37.6 degrees C, and electrocardiogram and serum potassium were within normal ranges. After the diuresis with mannitol and furosemide, the urine became clear. On the 4th postoperative day, he was discharged without any complication. This case suggested that rhabdomyolysis can develop after sevoflurane anesthesia in patients with DMD.