Although D-penicillamine has been used for many rheumatologic diseases, toxicity limits its usefulness in many patients. Polymyositis/dermatomyositis can develop as one of the autoimmune complications of D-penicillamine treatment, but its exact pathogenesis remains unclear. We report a patient with primary biliary cirrhosis, who developed polymyositis while receiving D-penicillamine therapy. We described the special clinical course of the patient. Patients receiving D-penicillamine therapy should be followed carefully for the development of autoimmune complications like polymyositis/dermatomyositis.