A patient was a 67-year-old female, 153 cm tall and weighing 47 kg. In 1988, she noticed sudden hypotonicity of her extremities, which led her to visit our hospital. Diagnosis of polymyositis (PM) was made. Treatment started with prednisolone 60 mg.day-1, followed by 2.5-5mg.day-1 as a maintenance dose. Her clinical symptoms were alleviated. However, in October, 1994, colon cancer was found and she underwent sigmoidectomy. For anesthesia, thoracic epidural block (Th 11/12) was performed. No problems occurred during and after the surgery. The following points must be considered for anesthesia of a patient with PM: (1) enhanced or delayed effect of muscle relaxant, (2) pulmonary complications--aspiration pneumonia and lung fibrosis, (3) cardiomyopathy--arrhythmia and cardiac failure, (4) steroid supplementation. In our case, because cardio-pulmonary functions were almost normal, epidural anesthesia without using muscle relaxant was a successful method.