Introduction. Dermatomyositis is an idiopathic inflammatory myopathy with characteristic cutaneous changes. The disease belongs to paraneoplastic dermatosis. Association of dermatomyositis with malignant conditions has been described in various studies. We present a patient with paraneoplastic dermatomyositis associated with metastatic rectal adenocarcinoma. Case report. A 66 - year - old man was hospitalized in our Institute due to skin changes and myopathy in October 2006. According to the medical documents and history, he underwent surgery because of rectal adenocarcinoma in April 2006. Skin changes appeared 5 months before, while aggravation occurred 6 months after the surgery. The diagnosis of dermatomyositis was based on: characteristic clinical picture; the elevated serum level of following enzymes: creatinine kinase, lactate dehydrogenase; the presence of anti - Mi 2 antibodies in serum; electromyographic finding; and by histology of the muscle biopsy. Paraneoplastic nature of dermatomyositis was confirmed by computer tomography of the abdomen which revealed multiple deposits in the liver, by explorative laparotomy showing peritoneal dissemination and histopathological analysis that verified metastatic adenocarcinoma of the rectum. The oncological consulting team suggested chemotherapy which was not carried out because of the rapid lethal outcome. Conclusion. We report a case of paraneoplastic dermatomyositis associated with metastatic rectal adenocarcinoma and lethal outcome, and suggest a comprehensive evaluation of patients with dermatomyositis older than 50 years in order to exclude or verify the occult malignancy.