The case of a patient combining dermatomyositis and bronchogenic carcinoma is reported. Steroids and corticotropin brought about control of the dermatomyositis which became more evident after supervoltage irradiation of the neoplasm. The tumor response to this treatment was only temporary. The patient died 14 months after the onset of the dermatomyositis as a result of dissemination of the cancer. Postmortem examination showed an undifferentiated carcinoma with multiple metastases.