Widespread use of amitriptyline in clinical practice has led to extensive knowledge of its therapeutic and toxic effects. In cases of amitriptyline overdose, delirium, arrhythmia, convulsion, and adult respiratory distress syndrome have been reported, but amitriptyline-associated rhabdomyolysis has been rarely reported in the literature. Several drugs are associated with myositis or myopathy, but amitriptyline-related myositis has not been reported. We describe a 40-year-old woman with rhabdomyolysis and localized myositis in left proximal thigh after she had taken 625mg of amitriptyline. (Korean J Med 57:380-384, 1999)