Dermatomyositis or polymyositis as a paraneoplastic syndrome of hepatocellular carcinoma (HCC) is an uncommon event. Few cases have been reported in the literature. We herein report the case of a 55-year-old man with chronic hepatitis B and alcoholism who presented with skin rash. Abdominal computed tomography revealed multiple hypervascular liver tumors consistent with HCC. He subsequently developed dysphagia with proximal limb weakness. Laboratory tests and electromyography demonstrated inflammatory myopathy. We therefore diagnosed the patient with HCC-induced dermatomyositis. Prednisolone and anti-viral therapy were administered; however, the patient died two months later due to the progression of the disease. We review the cases of HCC-induced dermatomyositis and polymyositis in the literature.