The coexistence of polymyositis and primary biliary cirrhosis is rare. Both are characterized by chronic inflammation and immunological abnormalities. We report a case of 54-year-old female patient presenting with these two autoimmune diseases. She exhibited symmetrical proximal muscle weakness and elevated serum levels of muscle enzymes. Polymyositis was confirmed by electromyography and muscle biopsy. The diagnosis of primary biliary cirrhosis was based on increased serum levels of alkaline phosphatase, IgM immunoglobulin, presence of antimitochodrial antibody and characteristic liver biopy findings. This is the first case who manifest polymyositis and primary biliary cirrhosis simultaneously in Korea.