Dermatomyositis (DM) is a rare and idiopathic inflammatory myopathy with characteristic cutaneous manifestations. There is a well-recognized association between DM and cancers. In Korea, several DM cases have been reported to be associated with stomach cancer, breast cancer, acute lymphoblastic leukemia, lung cancer, and tonsil cancer. However, an association between DM and lymphoma in Korea has not been reported up to now. We report a case of DM who developed diffuse large B-cell lymphoma 1 year and 8 months later