Dermatomyositis is a rare disease of unknown origin characterized by symmetrical muscle weakness and specific skin lesions, A link between dermatomyositis and internal malignancy has long been suspected. A 76-year-old male patient presented with erythematous patches and crusted papules associated with muscle pain and weakness of The upper extremity. As he showed characteristic clinicals features, and abnormal electromyogram and muscle biopsy findings, he could be diagnosed hy dermatomyositis. Three months later, following appropriate treatment, pain and weakness of the upper extremity was more aggravated. On the radiologic examination advanced gastric cancer with multiple metastases were found. (Korean J Dermatol 2001; 39(1): 123~126)